On my tt ( hybrid ) I took the rear spare tire and part of the bracket off the rear wall of the trailer and welded a "L" shaped 2" square with a receiver end. That I then mounted (bolted) to the trailer wall where the spare tire bracket was. So I used the part of the spare tire bracket that was still mounted to the trailer wall and made that "L" shaped bracket that bolted to that. This way I didn't have to attach anything to my rear trailer wall. I carry 3 adult bikes.
Hear is a few pictures...
So at the campground I'll take the bikes off, then pull the pin, and that take the bike rack off from the receiver. I have to do this to open up my rear bunk bed.
This is a 05' Aerolite trailer. We are looking at the new 12' Aerolite hybrids that now have a 4" solid bumper. It is stronger that the thin metal bumper I have on my 05'. I believe the Colemans and Aerolites are both made by Dutchman in the same plant. So I'm going to bet are like the new Aerolite's....