I know someone who has done England to Australia and after Turkey and the Stans they wound up going through north india and then through tibet, down through bits of china and south east asia (not sure of the geography but that's the way they went). They said not to go down into India because there is no way out across the surrounding sea!
Crankarm mentioned a crazyguy journal by Peter Quaife. I know Peter very well and he did a long ride across tibet about 3 years ago, and also wrote it up in a crazyguy journal so you can look that up too. This is going to sound very random, but about half way through Peter's journal he describes how he meets a guy called Tim. Tim is the guy who I mentioned in the above paragraph, who rode from England to Australia. I know that Tim did an online blog or journal of his trip and that it got hacked, and is now lost. But if you contact Peter through Crazyguy, he will be able to put you in touch with Tim, who I am sure will be more then happy to share any tips he has. Alternatively you can PM me and I will let him know you want to have a chat and see if he consents to me passing you his email addy.
I am not sure whether Peter even has an account on here - if so it will be under the name PQ - but I'm pretty sure he hardly ever comes on. Either way the guy can talk for England and would be more than happy to offer you a few tips and to put you in touch with his friend Tim (I've met him and he's a very nice guy).