RV Panel is up and glued into place. I also used the plastic snap pieces between the planes for a clean finished look.
Upper crown molding is 9" chip board with carpet glued on. Each piece is 4ft long and attached with screws to a wood block that was fastened to the box. This way I can remove it to run my lights or to install speakers.
Between the doors I had a funky size gap that would have been difficult to finish, so I wrapped some carpet and screwed it in.