hi thewaytodawn, I worked for a China adventure tour company who focus on riding/driving tour in China. hope i can help.

For China part, like the other friends on above said, It's not cheap for solo rider ride in China. the cost of permit, guide and supporting car is necessary, and solo rider need to afford that on own.

So the normal way are:
1. to make a group to share the cost.
for this item, like i said before, maybe this is a good idea: to mix the self-driving group and riding group, then the guest's vehicle also can be the supporting car to save the cost.

Still need to note the points:
a. in principle, the motorbike cannot riding on the expressway in China. and the whole group need to follow a fixed route, therefore the vehicle should follow the motorcycle to explore the normal way(national road, county road etc.)

for example: if you would make a group driving from Mongolia to Laos, then you should take the normal way, there should note the driving hours each day for cars.
but if you make a group go through the Xinjiang-Tibet, not too much problems cause it's all the normal way in the highland.

b. Even if you make a group respective into "car" and "motorbike" group, you'd better to choose the similar type of "vehicles", like 4x4, sedan, big campervan etc. different vehicle may require different road conditions.

2. to join into a big group, i recommend a UK company before: Globebusters.com | Home, they do the global riding tour (from Europe to China then Southeast Asia, even then ship to AU).

Hope these info make sense for you. welcome to write to me for learning more specific information refers to China at abby.zhang@navo-tour.com

Cheers~