Well, the 2920BH is 32' tip to tip and my owner's manual recommended driving in 3rd gear with tow/haul engaged. I did notice the pushing/pulling decreased while driving in 3rd. I'm not opposed to driving in 'D' though.
It is a E2 rated at 1K lbs. I did have the electric brake installed.
No, the teck spent over an hour walking us around, in, and under the TT but we didn't drive it out of the lot. That would've been great. I was slightly disappointed after signing the paperwork as it seemed they couldn't get me out fast enough (elderly couple was waiting to have their FW hauled in). I didn't see them hook it up. They already had it hooked.
I did notice more on bridges...figured it was the difference in the solidity of the bridge vice Interstate driving. It decreased with slower speeds (60 in a 70, etc.)