Thank you all for the replies. I can totally get behind doing the cheapest thing first to start out, but I'll need to figure out what that actually is. I guess my first move is to try and see what heel clearance would be like on my Trek. If it looks like I could clear panniers, then that will make things a bit easier to decide. I've read that using a 4 point rack with P-clamps is better than a 3 point rack like the Tubus Fly. Would you guys agree with this?
Staying under 20 lbs should be easily doable since I'm not really worried about taking much other than a sleeping bag and some cold food on top of some emergency things. Water will be relatively accessible along the way, and I normally ride with two one-liter bottles.
I'm excited to get going.
Edit: Here's what I'm looking at for heel clearance.
