Travelling through Gansu presents no special problems except for the province-wide requirement that foreigners intending to use long-distance buses purchase a special insurance policy from the state insurance company, PICC - regardless of whether they have their own private travel insurance or not. As is normal with such regulations in China, it is erratically enforced: often you are asked to show the PICC certificate before being allowed to buy a ticket, though sometimes not. You have very little chance of claiming anything should you actually have an accident; the insurance is basically to prevent the authorities from being sued. PICC certificates of two weeks' validity can easily be bought from PICC offices in all Gansu cities (and, for a small commission, in some bus stations, hotels and CITS offices) for between ¥30 and ¥50. Certificates valid for one week cost ¥15 and are only available from PICC offices.