Any ideas on how to get my TT from Wisconsin to Florida?

Your catalytic converter may be suspect and that will rob power. I'd also suggest to take it out of cruise control and operate manually. You do have the van loaded up with weight. Have you packed that much in previously?
I'd also suggest to take the rig to a garage (not the slow idle guy) and have them test drive it. You have too many variables to this problem to diagnose any otherway.