Well, Ive been home for a couple of days now. I've checked everything people have suggested on this forum. Tires, wheels, wheel bearings, all the lights, chains, hitch, windows, walls, propane tank cover, crawled under the trailer, no leaks, climbed on top of the trailer, checked the roof, vents, sky lights, air conditioner. Found absolutely nothing wrong with anything.
Thanks everybody for all the suggestions. I guess somebody thought it would be funny to do that, or whatever they saw somehow corrected itself.
Anyway, my next plan is to purchase an Emergency Road Services Plan just for my peace of mind. I had all kinds of visions of the kind of things that could go wrong out on the highway.