We use the Arvika 2" receiver mounted to the A-Frame of the TT with a Thule CrossTrack carrier. Works great. The problem with the rear bumper mounts is the "whip" you get back there, which can lever off the bumper, or break the rack. Not nearly as big a problem over the A-frame, it is a fairly smooth ride.
Unfortunately though, you do have to pop the rack off before dropping the bunk; an extra 5 minutes in setup time. The Arvika sits below that level and does not have to be removed.