Tom is much more well read about touring bike geometry and touring bikes in general but I'll tell you what I know. I had a REI brand road bike and a Specialized commuter bike. We brought them down to Saturday Cycles to see what the experts there thought. They said I could use my road bike but if I could afford it a Surly Long Haul Trucker would be an excellent choice for the tour. Tom and I decided to sell the two bikes to get some mula to put toward a new LHT. Craig's List attracted weirdos and scammers but KSL.com worked like a charm. So we purchased my beautiful bike, rear/front racks, 4 panniers and a handlebar bag. I got really sore by the end of last weekend's ride so I am going to test out a Terry saddle tomorrow.