I built two seats with hinged lids prior to the trailer's arrival (they'll double as a bed with middle section inserted) and folding bunk beds for the kids.
Over the weekend I inserted 1" foam insulation in the walls, ran 12V wiring for outlets and lighting, sealed up some cracks with spray foam, and added 2 exterior lights. I found that a table saw worked great for cutting the board insulation.
Next up is to insulate ceiling (1") and add headliner, add ceiling lighting, and insulate beneath floors (2"). I plan to put a freezer converted to fridge in the nose and once that arrives I'll build the base cabinet housing PD4045, all electrical connections, and 2 6V Costco Golf Cart batteries (enclosed box vented to the outside). Had a long time to plan while the trailer was on order so I have most of the parts (still end up making multiple trips to Home Depot for odds and ends).
Will post as I make progress. While I plan to build this out pretty quickly, any comments or feedback is appreciated.