My first mod was to add some convenience to the rear bunk and dinette storage areas by adding drawers.
I used white pine for the sides and other structure, and Birch for the bottom of the drawers. Easy to work with and pretty light. Table saw, chop saw, bit of glue and a few screws on the corners is all these took (the screws were mostly to help keep things set while the glue dried)
The drawer slides are 24" (Lowes) and are rated at 75#. Lowes also sells the same handles that came with the camper.
Installing the slides was the tricky part. Had to screw through the face on the dinette side, but the doors cover the screws at least so they aren't all that noticeable. Also had to move the latches up a bit so they didn't obstruct the drawer movement.
Keep in mind, my day job is running an IT Project Management office, so wood working is a 'measure 2x cut then cut it now measure it again to see why it doesn't fit now cut it again oh crap too much have to start over' kind of thing lol
I have a couple more already made for under the front bed, and another small drawer for under the kitchen counter right at the door. Will post those after I actually finish.