Well my experience with a crossing the Pakistan/China border is: Go out of China NP, return on the bike NO way... its a export thing. Pay and Pray

Inner Mongolia/ Outer mongolia same deal as pakistan. Pay and pray

China/Laos is a different story, coming and going is rather common and while a guide helps, not completely necessary.

Oh and Rehan please let Euphonis and I know when your in Shanghai, like to meet you and hear about the ride....