From Chengdu to Litang (Kam), Xiancheng and Zhongdian (Shangri-la, Yunnan).

. A good source is Wiki-Travel.

. You must verify that the Litang region is not closed to foreigners. It's generally open! Go there by public bus from Chengdu.

. On the way, in the Sichuan plain, you can visit the Great Panda Research Center and, just before the mountains, have a stop in Luding, to see the bridge (a famous albeit tragic place of the Long March).

. You must stop for one full day (2 nights) in Kangding, to accustom yourself to the altitude. Kangding is at 2300m above sea. This is a relatively interesting place, as it shows the transition from Han to Tibetan culture. Around Kangding, there are certainly very interesting places to visit.

. The road from Kangding to Litang is absolutely wonderful, with a beautiful and spectacular landscape, with large Tibetan houses in every village. There are at least 2 passes at more than 4500 m. Some Chinese people go there by bicycle (and continue to Lhasa!).

. Litang altitude is a bit more than 4000 m. Be careful, walk slowly! Visit the monastery (15mn walk from the center), and walk in the city to observe the fascinating Tibetan life. There is also an interesting market in the center. Shops (restaurants) are owned by Han or Hui (Chinese Muslim) people. The individual houses are often very beautiful inside (I could enter one; it will be better if you speak a bit Chinese: local people often speak both Tibetan and Chinese).

. You cannot continue to Lhasa (it's forbidden -at least for individual travelers-); so an interesting possibility is to go south to Yunnan province. The first day, you will go (by public bus) to Xiancheng, a small but relatively comfortable city, inhabited by Han, Tibetan and Hui people. This is a very beautiful trip. Next day you will go to Zhong Dian (aka Shangri-la). Along the way you will cross very interesting Tibetan villages and see some large Tibetan monasteries. From there, you will certainly go in one bus day to Lijiang (wonderful but probably crowded).

Caveat:

. Do not go there during the Horse festival of Litang (it's crowded).

. Go there in summer: during other seasons, the region can be extremely cold!