Doing a tour like this requires the proper bike. Sure, many riders will tell you that you can do it with anything, and although this may be true it is certainly more enjoyable with a well-adapted machine.
For my buddy the choice was obvious. He rides a Triumph Tiger 800 XC nicknamed Hobbes. He bought that bike a couple of years ago with the purpose of touring with it, and that is what he has done! Last year he did a 1 month tour around Europe as his first big ride, and with the bike properly set up for such a long trip with all the necessary panniers and a comfort seat, he was well used to it for this year. It is a perfect touring bike as it is nimble and has just the right amount of power.