There a lot of motorcyclists who do global trips like that, along with all the issues of getting vehicles in and out of countries etc. May want to look at some of their blogs and books. I wouldn’t plan too far into the future, as well laid plans tend to fall apart at first contact. Be detail-oriented in terms of visas and other such requirements, but also be extremely flexible and tolerant of when things don’t go your way. Sometimes those are the most memorable moments (in a good way). Be cognizant of local situations and the geopolitical climate where you’re going. In most cases it doesn’t make much difference as people are people wherever you go, but when dealing with officialdom it may make a difference.
The CIA World Factbook website is a good resource to figure out what a country is like and their history, at least from the American perspective.