I just picked up a trailer for the boat I've been building, and after bringing it home, crawled under the truck to look at my smittybuilt bumper/hitch and where it mounts to the frame. I'd towed a heavy trailer all the way to AK from CA, and the bumper/hitch had angled down somewhat during the trip.

Anyhow, I see how the frame is a C section for about the last foot, and was thinking of boxing it in all the way back so it will be stiffer where the bumper/hitch connect. Anyone done this, and anything to look out for? I'm thinking 1/8" plate ought to be about right, and figure I'll cut out some access windows to access the rear bed mount bolts.