They are on the outside portion of the frame. Requires a deep 9/16 socket and a 3/8 drive ratchet. Most you can probably get with a wrench, except the ones in the far forward corners. Once you crawl under there, you will see the brackets. Seems to be a pretty common thing. I also remembered seeing a post a few months ago about someone with the same TT as me having bumps showing up under the linoleum flooring, which was bolts for the flooring that were loose. Well, I have those starting to show up here and there as well. Not bad, but as I have spent more time in my camper I have noticed more. Hopefully I can pull the under belly to gain access to tighten those.