4 - 1 1/2" Pipe hangers screwed into the upper front horizontal support in the pass-thru storage area.
This photo is a view from the left side storage door.
This photo is from the inside with the bed lifted up. Also, I added a simple wall of 1/4" plywood glued and stapled to a 1"x2" frame. It's attached to the existing tailer bed support/cabinetry sides with 4 screws for easy removal.