Well, I can say you have to do a bit more than that, because you cannot get all your visas ahead of time, oh that it was so easy!!!
Even trying to get a visa for one country in the middle of the leg, may mean being on the ground near the border, then sending your passport back home to get it stamped.
You will need to do exactly what I am doing now, trolling these and other pages, trying to find the magic bullet.
You will have to visit many websites for each country along your route, contacting the embassy etc etc.
Each visa is of limited time, so unless you plan and stick to a strict time schedule(with NO problems along the way) then it will be very hard to do.
EG- Maximoto has been stuck in Pakistan for a month trying to get a visa for Iran, so she can continue westwards.
Just one of those things that make the adventure I guess
The other things to consider are weather constreictions on the route, can you get through that pass right then, that also means you have to have those visas to cover that time period.
Sorry to sound a tad negative, but I can say, that doing the US and all the way south was very easy for me(Ozzie) because the only visa I needed was for the US all the rest of the countries were like Europe, nothing needed.
Cheers and good luck
If you do find the Holy Grale, please let me know
Cheers
TravellingStrom