Thank you! Yes, that is a Lego wheel and rotation plate turned into a Caster assembly. It was easier than making the whole thing out of brass and a 1/43 car wheel to see if it kinda works. It's still a testing phase of the trailer.
Once i make a better caster, i'll be ready to: knock the trailers mounting eyes off, make the raise/drop arms, put eyes on those arms, shorten the arms on tow bumper. It works kinda ok so far, but it should be better.
In talking to people who were around when these trailers were more common, it's interesting how many didn't remember them!
This will split into another thread soon, but which sounds better?
Assembled 'framed house' scenery
Knock-down 'framed house' that can be unloaded from trailer and raised by Crane somehow?