I am bicycling around the world supporting cancer research and want to arrive in China from Nepal

Before making an application, you should be aware that 1) China does not normally grant tourist visas to persons not applying for one in their country of citizenship or residence; 2) you will be entering Tibet which requires a special permit known as Tibet Travel Permit (TTP) in addition to your ordinary Chinese visa, and it takes 4 months minimum to prepare a TTP and local rules require you to have a licensed Chinese guide; 3) most border crossings between Nepal and Tibet are closed. There is also very little information on the internet for non-locals applying tourist visas in South Asian countries but, given your situation, you should try the one where you can directly submit your application to the Chinese embassy/consulate instead of a visa center (which is run by a third party) given your commendable cause. Good luck.