Dave, I think that's a very sensible analysis. I, too, would be concerned about taking a camera that's entirely new to me on a big trip. Plus, do you have lenses that would work well on the FX body, or would you have to rent those, too? Or shoot the D800 in DX mode, I suppose. I don't see much downside to getting the D7100 in your case. I suspect that even if you do sell it to move up to the assumed D400 you'll be able to get a good price since the street price of new units isn't likely to drop much for a while.