Take this advice for what it's worth. I've never done a trip like you are suggesting, and my experience of the region is limited to a couple of weeks backpacking in India rather too many years ago.
However I did want to make a similar journey a while back and spent some time planning.
I came up with the idea of riding a 26" wheeled bike with drop bars. I was tempted by a Dawes Sardar, but I think a 26" LHT would be at least as good. I liked the idea of stronger wheels, Less bottom bracket drop, and bigger tyres for the unpredictable road conditions.
When I was planning/dreaming the Rohloff was very new, and much less proven, but I did give it some serious consideration. In the end I decided I would rather have a dérailleur. A Rohloff might be less vulnerable and more durable, but if something goes wrong it will be a problem. However A derailleur is more likely to be mendable and parts, including whole wheels, are much easier to find.
That might have been mitigated by the extra reliability, but what finally swung it for me was that for the weight and cost penalty of the Rohloff I could buy and carry several spare dérailleurs!
I felt that if I was going to spend a year abusing myself and my bike in occasionally difficult conditions something was bound to break. I decided I wanted to give myself the best chance of mending the bike myself, and the money saved initially would give me a safety net if my body let me down.
Last edited by Fat tabby; 12-11-11 at 10:57 AM.