I would focus on getting your load slimmed down to an absolute minimum. A single speed bike can be great for touring but not if you are lugging an extra 30 pounds or so up and down the hills all day. How much are you planning to pack?

+1 on loading up the bike and going for a test run before the big trip. You might find some motivation to ditch a few extra pieces of clothing, the espresso machine, and the extra books so as to make your time in the saddle more enjoyable.