I`m in Japan, taking ferry island hopping to Tiawan and arriving HK end September, cycling towards Tibet in Yunnan part of China, probably take train and bus part of way, if I dont make it to Tibet before the winter maybe scoot down into Laos from Kumming instead- anyone interested?
There is a Tibetan prefecture in the north of Yunnan Province around Zhongdian.
You may be taking more train and bus than any thing else. You can scoot down by plane from Kunming - Laos (via Vientiane). Otherwise, you need to go to Jinghong (Xishuangbanna) in southern Yunnan Province and ask for directions to the Mekong River
BTW Golden Week begins 1st October