Heck, if you're going to be not too far from a bike shop, I'd carry a simple tire. With my light touring setup I use a Maxxis Detonator 25c on the front (as big as it will take and free, Tinker Juarez gave them to me) and carry one for a spare on the outside of my pack, folds up nicely. Over a thousand miles with no flats on it, I do run a Conti Contact 28 on the rear but still got gobs of miles left on that, no flats.