... check out eastern Sichuan province - it's absolutely beautiful. Not crowded, not polluted, very Tibetan. I recommend contacting the Extravagant Yak travel company (Chengdu) and asking what they can set up for you. Extravagant Yak | Tibet Travel Experts You may even want to venture into Tibet.
We had a lovely 9-day holiday in the Kangding and Danba regions of Sichuan, driving for one day from Chengdu, staying 3 days in Kangding and touring around there, then driving for a day to the Danba region and staying there for the remainder. Amazing views, extraordinary altitudes, fascinating people and food, and a guide who spoke excellent English, Putonghua, and several Tibetan dialects. You don't have to hike or trek if you prefer not to (I had a sprained ankle and knee and could not), but it is helpful if you can walk around the villages. In our opinion it's the best part of China by far!