In 1950, Mao's single minded bloody idealism took him to Tibet to get rid of social hierarchy, not realizing 2/3rds of land in Tibet was controlled by nomadic herdsman. Since the occupation china has committed an endless list of human rights atrocities culminating in the genocide of 1.2 million Tibetans, along with enforcing policies to marginalize them from their own country, extracting resources back to china and limit the free practice of religion.
Free Food and shelter
Camp with nomads
Nomad tent communities are found in Amdo and Kham. In Amdo the biggest camp is on the Tsekog Grasslands at 3500m and a 5 and a half hour train from Lhasa. During the summer, white and black Tibetan tents can be seen everywhere. Your fine to set up your own tent but try and talk to the nomads, they are often extremely hospitable and may offer you stay in their tents and offer you butter tea and yak jerky. Ask to help where you can and try your hand at milking yaks, herding sheep, and riding horses. Offer them clothing and food if you can as a parting gift. The Tagong grasslands in Kham have a long cultural past but suffer from thievery, violence and banditry which have made for exiting stories of people staying there but perhaps not for those looking for a relaxing time.
Stay at Buddhist monasteries
The best are in out of the way places where you get the feel of the gompas, if they are small and remote; Chiu and DriraPuk and ZutulPuk in West Tibet, any of the Lake Manasarovar gompas have views not available elsewhere on planet earth. There are several on the northern route from Lhasa also, off the road a little.
The big monasteries run guesthouses separate to the monastery like dorms, often very basic, where you can stay for the night, but generally you do not have any contact with the monastery or the monks themselves as the Chinese authorities are keeping a close eye. Many travelers avoid these for having too many Chinese influences, too political or too metropolitan but some of the more notable ones are at Ganden, Samye, Tsurphu, Rongbuk (Everest) and the Kailash trail. It would be wise to bring your own sleeping bag and a few extra munchies to add to the basic food. You can usually get Thukpa (noodle soup) meat and potatoes and/or perhaps fried rice.
Tibetan monasteries are still places parents send their kids to get an education so most young monks know some English. If you write it down and keep it simple, they'll probably understand.
Arranged tour companies such as the Himalayan Adventure Company, Snow lion tours and Tibetan connections are the only legal means of traveling since china stepped up security after protests.
If you keep your head down it is possible all be it sketchy way to getting round without a permit. Often if caught they'll just send you back the way you came.
The road from Golmud is possible to travel by way of hitch-hiking on trucks if you are well prepared (camping equipment, food and water for a day). Expect to spend a few days. There are police checkpoints on the way but the only one that is a problem is the one 30 km or so out of Golmud. If you walk around it and a few km beyond you should be able to get a ride without too much of a problem. There are plenty of places to eat on the way but be prepared to get stuck in the middle of nowhere. There are also are places to sleep ranging from truck stop brothels to comfortable hotels, however these should be avoided as you're likely to get picked up by the police.
From Kashgar much of the way is technically off limits. However there is a steady stream of hardy travelers coming this way, usually hitching rides on trucks. The road is totally unpaved for over a thousand kilometers with villages and water few and far between. The main advantages of this way is that it passes by Mount Kailash and through a beautiful, very remote region inhabited by nomads. You should be very well prepared to travel this way and take everything you would need for independent trekking: camping equipment suitable for freezing temperatures even in summer, a good tent and at least a few days of food (there are a few truck-stop places on the way but not always when you want them). Expect the trip to take two weeks or more. From Kashgar it's much farther to go to Lhasa via Urumqi and Golmud but the better transport (trains and good paved highways) make it no more time consuming to travel this way. There are many interesting things for the tourist to see on the way and it is worth considering traveling this way instead of via Mount Kailash.
Hitchhiking can be a good way to get around the country for someone who is flexible and has a lot of time. It can, however, mean you end up getting stuck without a lift for days. In the west of the country this probably means hanging around truck stops, as the distances are far too long to walk, and finding water would be a major problem. Trucks often break down though and it can take a long time before the journey continues. Hitchhiking in general is not free and a small fee is expected. In central and eastern Tibet, there's more water and villages, and so walking becomes a more reasonable option. In short, hitching may or may not get you to your destination any quicker, but at least it offers a change of scenery.
Public buses will refuse you ticket without a permit but the pilgrim buses are often free charge and trek out of the capital at ridiculous hours of the morning towards the surrounding monasteries with hoards of local monks, pilgrims and traders. It is here you meet the real people of Tibet, often the Tibetans are happy to see you exploring their country and welcome you with open arms, getting off these buses at one of the monasteries is often the start of a great adventure. It is from these places, or from being dropped at your request in a passing hamlet, that you can find tractors traveling up to mountain top monasteries rarely visited by tourists, quarry trucks of miners heading deep into the mountains for weeks of work at a time or boats setting along the river bringing in and out fresh veg from surrounding villages. Be warned, the big monasteries all contain police outposts that do check you out!! Keep your head down and think about where you're heading. Once on the road it becomes a glorious freedom... you begin to depend on the one truck a day/s that drives the routes between hamlets. Time becomes a concept of light and dark and you find yourself living the life of a sworn monk in the remotest of temples high in the mountains.
There are a surprising number of tourists traveling Tibet by bicycle, both foreigners and Chinese. The roads vary from rough dirt tracks to good quality paved roads. There are restaurants, truck stops and shops scattered around often enough so that you don't need to carry more than a day's worth of food (with the important exception of the west of the country). The roads are often well graded, being built for overloaded trucks. 26 inch wheels would be preferable as 700c (ISO 622) are almost unknown in China. Good mountain bikes are available in large cities of China or in Lhasa. Golmud is not a good place to get a bicycle (assuming you want it to get you past the check point 30 km outside of town). Cyclists have reported that distances cited in the Lonely Planet guidebooks can be quite inaccurate so be very well-prepared. or horseback along well layed out trails or hitchike with freindly locals.
Most classes are taught in the Tibetan language, but mathematics, physics, and chemistry, are taught in Chinese. Tuition fees from primary school through college are completely subsidized by the central government. Though they openly propagandarise e.g. portraying the Chinese as liberators and the Dalai Lama as a tyrant.
Free Medical Care
There have been numerous reports of forced sterilizing, go to people you can trust.
Cell phones (voice and SMS text), e-mail, video sharing, and internet are heavily monitored and censored by Chinese authorities as part of "The Great Firewall". Any site or wording that makes reference to the Dalai Lama, the Falun Gong religious movement, potential acts of terrorism, or anything that may portray the Communist rulership in a bad light are blocked or censored. It is common for folks to receive text messages and e mails with words taken out through state required automated software. Many internet cafe computers can be required to keep special hardcoded spyware installed by the factory for "safe surfing". Enough messages sent out that need to be blocked may attract attention of militant Chinese authorities, so assume all electronic communications to be tapped.
Of course, there are from time to time proxies and various ways around the censorship. However, these work arounds are shut down as soon as discovered and change often.
Buddhist Festivals are lively events that bring together Tibetans from all over the plateau. The more than 100 major and minor festivals that take place throughout the year include horse racing, dancing, singing, praying, and displays of religious artwork.
Find Tibetan art in Repkong, known as the cradle of Tibetan arts it is famous for producing some of Tibet's best thangkas and painted statues. The city's main monastery, Wutun Si, allows visitors to meet the local artists and purchase a painting or two.
A large amount of Tibet is open pastoral land, so you may be tempted to plant weed to fund the Guerrillas or your own stash. Or maybe smoke a bowl to help meditate with the Buddhists..
IF you try to sneak drugs over Chinese controlled borders OR try to buy or sell drugs in Chinese occupied areas.... you risk not only imprisonment but your LIFE and there is little any embassy or amnesty group can do to help you!
China has some of the harshest drug laws in the world, more so than some Middle Eastern countries. There are many cats that went on vacation to Hong Kong or other places in China serving 20 year sentences for just a joint! Growing your own or selling is worse! China regularly executes drug sellers. They even have an annual televised event where they round up everyone to execute in public to celebrate "International Day Against Drug Abuse and Trafficking"!
Good road maps of Tibet are common in China, but only in Chinese. These are of limited use even for people literate in Chinese as the Chinese names are very different from the ones used by the Tibetans. They are useful for reading road signs, even for people with low literacy in Chinese.
The Star publications map is probably the best. Amnye Machen Institute publishes an excellent map of similar scale and detail but with the Tibetan names, with a version written in Latin script and one in the Tibetan. It makes a useful companion. Tibetmap.com has a free downloadable set of maps covering much of Tibet with detail almost good enough to use for independent trekking.
Ask the locals to give you a sky burial so you can live on as gracious birds.
Silencing by Torture, imprisonment and executions is still rife under Chinese occupation, if you are at risk at all try to escape over the border. The Tibetan-Nepali border is heavily guarded and people have been shot to stop them reaching the Tibetan government in exile and because an agreement between China and Nepal to reduce the number of refugees entering Nepal.
Clean up so you leave no trace after trekking and camping. Only employ local Tibetans as guides, patronize local Tibetan businesses, and purchase supplies directly from farmers and nomads or in local markets. Invest in the next generation of Tibetans by supporting the Kumbum Shambaling Orphange School.
A sabotage action such as against the Qingzang railway line would go along way towards rallying people in resistance to China's military and cultural imperialism.
Tibetans' tendency in the 50s was to form large groups, complete with their herds and families, and so were easy targets for the Chinese Air Force. They also fought vigorous battles with large groups of Chinese soldiers in which they suffered heavy casualties.
This showed the need to stay mobile, only attacking in skirmishes with the element of surprise.
When you've shown to be a repetitive strain on the enemy's resources and there are other liberation movements in other areas of the country then China may be forced to hold a referendum on independence.
Though this is likely to be an over a 100 year long struggle, so one of the most useful strategies at this stage would be simply to try and travel outside of China to experience other liberation struggles and bringing inspiring stories and lessons back in person if possible or through media.
Hiding weapons underground and farming during the day to complete attacks at night is a Vietcong technique which has the benefit of the Chinese army not knowing their enemy, but leaves you unarmed to inspecting Chinese army and law enforcement.
Keeping mobile and hidden is best, trading service in return for supplies off locals when the coast is clear. Getting training in medicine before taking up arms would also be a plus.