Best Time to Gansu
Autumn is the season for harvesting most of local fruits, and the autumn scenery is quite beautiful and impressive, there is less tourists in Gansu comparing to summer, therefore the accommodation fee is relatively cheaper.
In a word, it is recommended to arrange your tour routes with your preferences for scenic spots. You can start from Xining and finish tour in Lanzhou, if you enjoy the azzure blue lake, golden rape flowers, white yak, green grassland, Gobi-desert, wind-erosion Yadan and colorful Daxia landforms. You may also enjoy the snow view on the way during autumn.
Or you can choose the route of classic single line tour: Ming Sha mountain -> Crescent Spring -> Mogao Grottoes. You can also go in the opposite direction, begin in Dunhuang and finish your adventure in Xining. Comparing to Qinghai Lake around tour, you could enjoy the beautiful winter sceneries of Qilian Mountains, and you will see much more grassland scenery than the Gobi scenery.