How long do you plan to be on the road?
East from India, I think you´ll face one of the challenges straight away (how to get to Southeast Asia, as there are obstacles in the form of the Himalayas, China, Burma & the Bay of Bengal).
But your already in the right place: browse this very forum, and also the Southern Asia-section for a few days, and you´re guaranteed to find plenty of info.
I actually posted a sort of map here before. If you like to see it, check out the thread: Routes north of the Caspian Sea - (the title is misleading, as the map´s got more or less all of northern, western and central Asia & Indian subcontinent.... and why I made it, all this is related to a series of articles on a magazine, so right now I´m in the process of making something similar about possible routes in SE Asia, and hopefully from the Americas, too).