The Old Man Mountain may seem expensive if you're new to touring but it's tough to get any kind of good rear rack for much < than $50, and fixing a broken rack on a ride isn't the most fun thing in the world.
If your frame is designed more for light weight than heavy loads keep an eye out for cracks and stuff for a while if you load her up with 75 lbs of gear. It's even more difficult to get a fancy carbon fiber or titanium (or whatever they're using on good road bikes these days) fixed by Bubba in BFE. Dedicated touring bikes tend to use steel frames.