hmm... i just got back from a tour, some of which was on the c&o canal. yesterday i did about 85 miles on it (crushed gravel, sticks, stones, etc) and 20 odd more through DC.
I was riding my 52cm lht and my friend was riding an old 700c specialized tourer. we both had b17s. He had 28c tires and i had 1.5s. I could hear his spokes creaking at the crosses and he and i were constantly expecting his wheel to collapse. he also experienced lower back and wrist pain, which i didn't get any of. my wheels are spinning straight and true, and the bike fit me great.
no toe overlap even with big mud flaps, etc etc was super stable on down hills got great cornering traction, rode like a cloud. felt a little sluggish on flats. for road touring i'd put on a bigger middle and outer ring. maybe just bigger by a tooth or two.