+1 on boxer briefs and baby wipes. I've tried many of the specialty skivies and they haven't been comfy for me. Hanes combed cotton tagless are my choice. There's no seam at the leg. Buy a couple travel packs of baby wipes. One for your jacket pocket and another in the tank bag. A squeaky clean pooper is a must. Try and eat fruits and foods that keep your digestive tract moving easily. Until your body gets used to long days in the saddle, you might get unpleasantly bound up. Hydration should error to the side of overdone. Sounds like a fun trip. With a heads up, you're welcome to bunk here in Lewiston.