1500 gets you a lot of good, but nowhere near "best" touring bikes, perfectly adequate, and also capable of what you want to do. And there are a million threads. Bikes in that price range are normally quite similar, or the dissimilar aspects are pointless, say one brand of no-name skewers vs another. So the frame is a big part of it, and the frame fit. I have bought a few bikes sight unseen and it turned out badly.

Early on you need to figure out how you are getting there and exactly how you will ship your stuff, this will have a big impact on your choice.