Whether or not the Chinese let people into Tibet or Western China, seems to vary at short notice and depends on what the minority people’s (Tibetan and Uigars) are complaining about having their counties colonised by Han Chinese.
Add to that the normal Chinese limitations on foreign registered vehicles ( you need a escort) I would hate to base a trip on getting through the Chinese Nepalese border.
I have been to the border, but was on a R75/6 back in 1978. No way you could cross then. When I was in Western China in 2008, the Chinese closed our planned border crossing point involving a 500 miles (beautiful) detour and would not allow access to Tibet.
Sent from my iPhone using Tapatalk