Gansu (甘肃; Gānsù) is a province in the North West region of China. Historically, it is the combination of the two regions, gan (甘) and su (肃), and marked the end or beginning of China proper depending upon if you were traveling east towards Xi'an or west towards Central Asia and Europe. Gansu's western frontier thus juts right into the borders of the vast steppes of Mongolia, the unforgiving deserts of Xinjiang and the high mountain wastelands of the Tibetan Plateau.
The northwest province of Gansu spans the Qinghai-Tibet, Inner Mongolia and Loess plateaus in the upper reaches of the Yellow River. The topography is complex and the climate unpredictable. The river valleys in the south belong to a subtropical zone while the north is an arid temperate zone. The province was a center for East-West cultural exchanges as early as the Han and Tang dynasties. Many people go to Gansu to seek out the the roots of world civilization. The 1,600-km-long Silk Road of the Han and Tang dynasties unfailingly brings the visitor to such places as the grottoes at Dunhuang (a veritable world-class treasure house of art), the Jiayu Pass on the Great Wall of China, Majiishan Grottoes of Tianshui, the Labrang Temple of Xiahe, the Great Buddha Temple at Zhangeye and the bronze sculpture of galloping horse in Wuwei.
Gansu contains some of the largest and most important Tibetan monasteries outside of Tibet province. Travel by local bus across high, frigid plateaus to reach them. Ride horses across the plateaus past yurts. Share lunch with Tibetan monks. Share yak butter tea with monks. This part of China bears almost no resemblance to Eastern Han China. Empty, wild, culturally and ethnically distinct, it offers some of the most exhilarating travel in the world.
Imagine 7 hours of travel across a high plateau in a rickety bus dating from 1970. Every few hours, one of your neighbors, swathed in yak wool, stops the bus, dismounts, and starts walking to the horizon. You can see for 20 miles in all directions. There are no towns in sight. It is an empty and riveting land.
Beware of the time of year you travel there. It is wicked cold even in May. In rural areas (the most interesting areas are rural), very few housing options are available. Probably, there will be no heat. So bring layers or buy a yak wool coat.
There is a Tibetan region in Southwest Gansu bordering Qinghai province, where both Chinese and Amdo Tibetan are spoken. Some local dialects in every part of province, but in general everyone is able to talk Standard Chinese.
The main airport of Gansu is Lanzhou.
Some train access. But to get to the interesting sites, local bus is a necessity. Think of it as an adventure. And get ready to use non-verbal communication.
Foreign tourists are supposed to get insurance for bus trips and are normally charged twice the regular fare paid by locals. This occurs in the main parts of Gansu frequented by tourists but you might be able to avoid this in the outlying areas. CITS sells a policy as well as the Peoples Insurance Company of China.
South Ride horses for days on a trek. Hike through the hills. Hang out in monasteries. If you don't like the outdoors, this is not the place for you. North Camels are an option for short trips in tourist locations.
Southern Gansu : Yak meat, butter, yogurt. In traveler's places, they often have scrambled eggs with tomatoes. Beware of local rice whiskey.
The most famous food not just in Gansu, but all around China is 兰州拉面 (Lanzhou lamian), noodles, everywhere in Gansu from ¥5.
Another choice is lamb (羊肉； yangrou).
Yak milk. Zhangye local spirits.
OK, the horses are fun, but perhaps not the safest option.