You need to join a travel agency first, like Travelchinaguide. Individual visitor is not permitted to visit the land. Besides, you need to apply a Travel Permit to the region. A qualified travel agency can handle them for you.

hi ,
if u are a foreigner, u need to get a visit permit there. I'm a foreigner and some time ago i just got there. and foreigners can not get the permit by ourselves and cannot travel independently in TAR. so whenever u wanna go, u need at least book an agency to help u to handle it.but dont worry the guide cannot be ur shadowing nanny only if u find an agency who can arrange private travel , during which u can have absolute freedom to decide where to go or stop
good luck:)