I guess that you can't journey into China from Nepal, Those who like to travel through China by his/her own vehicle or on foot have to find a travel agent in their own countries first. And then they should submit the document specifying the name list of the travelers, touring schedule (namely, port and time of entry, touring route, cities to call at and programs in China) and the vehicle information through the travel agent in their own countries to an authorized international travel agency in China three months in advance.