I don't worry much about the high end for touring since the only time I ever have much speed is when I'm coasting downhill. The low end is what concerns me the most. My lowest gear is 24 (front) and 28 (rear), and I've done ok on long tours with lots of steep hills, but would not have minded having a megarange 34-tooth option in the rear on some of the insanely steep hills. But you'll probably be fine without that. Also, just want to add that it's not only the rider's strength that's to be considered, it's how much abuse you want your knees to withstand. Having injured my knees touring in the past, I'd do just about anything to prevent that from happening again.