dlkcub,
Wow, thanks for the link! I searched the forums, but couldn't find anything that seemed relevant. That pocket stop adjustment was *exactly* what the problem was.
I was very level at the site I had the most problems at, nothing on the roof or between the seals, etc. I was getting really worried.
The problem is that the new-style pocket stop adjustment on my starboard side, rear shell, front arm (don't know what the back and front arms for each shell are called), was loose - I could turn the bolt by hand quite easily, which isn't good because I suspect the road vibrates it. In fact, I confirmed that when I fixed it earlier today, drove about 5 hours, and had to repeat the "adjustment" again to set up. I'll be applying some Loctite to the bolt when I get a chance.
If anyone from the factory is reading this...it would be nice if the bolt would stay firmly in place, and not rely on the friction of the threads alone...applying Loctite seems to be at least a good suggestion.
Thanks everyone who replied - you saved my trip!
I'm in a sunny Pennsylvania campground. The TM has towed wonderfully, although I must admit the PA turnpike outside of Philly, complete with narrow lanes and construction, made for an anxious drive - but I can only imagine what I would have thought with a longer and taller trailer that swayed when I was passed!