I like what mtnroadshas to say, especially about his Trek 970. I have a Trek 830 from 1988 that is not up to the quality of a 970 with regards to wheels/hubs and some other componentry. But, it has a bullet proof frame. It's set up for my personal physical situation so it's a little different than what most people consider normal for long rides. Still, it works for me and will pack like a mule and climb like Jeep. It was to be my tourer until bought a Trek 520 off CL. Fully loaded/racked and with Nitto upgrades and a Brooks B-17, it cost me $550. It's a '98. New ones go for $1,100 around here.
Bottom line, it can be done. There are lots of good bikes out there for sale.