i'll say go to Yunan and SIchuan
a month is anough time to get to kunming from there clibe up north west to dali, lijiang, tigrt leaping gorge, shangrila and from there with the sichuan tibetian higheway to changdu. from changdu back to kuning and out. the weather in the east cost and the main land right now is very hot while in kunming, west yunan and west sichuan the weather is simpley great...around 20cel during the day and a little cilder at night. the eazy way to get to kunming i belive, is actually from bangkok. thai ariways and china eastern are flying there on daily basis, and kunming is a great fun city.