Closest to a WR250R would be the 鑫源x2, copy and paste that into a taobao search field and you see lots of them.

If your only there for business and the bikes is just a tool to get around, there are lots of cheap 150cc versions designed for the Chinese roads, ones with lots of racks to pile on . A dirt bike is never ideal to carry stuff on, they have these types bikes that are very utilitarian. Yingang makes one of these they call it a Mountain King 銀鋼, its a CG150 it probably be a good bike for your purpose.