I´m no expert on the subject, but it is my understanding, that as a foreigner you won´t be able to cross anywhere between China and India. And you would be able to cross between China and Pakistan, or China and Nepal, but the latter means going thru Tibet, which makes things even more complicated, and costly.
But lately, Chinese travel restrictions have become even worse: for Tibet, you officially need a group with the same nationalities. And also, you cannot do inter-provincial travel with a vehicle (I must say this one was really surprising, and very recent, too; is there a way around it, I guess the Chinese tour operators should know).
And, as you probably found out already, it will be very expensive.