I went down that rabbit hole at ADV. villageidiot did a good buildout report on his. I've got tons of bookmarks and ideas that are slowly congealing into a plan. For the outside, a roof rack, cargo basket with solar panels inside it and an awning mounted to the side. I may or may not have a powered fan installed. Still debating it inside since there are windows that will open already installed in the rear. It's wired for 110, so a simple small box fan will suffice, I think. LED lighting too. Low draw, small size and bright off a 12v power distribution system based on two deep cycle batteries separate from the internal 12v system.
I'm leaning towards an RV dinette style bed in the rear with storage under it. I want a small powered fridge for keeping stuff cold on a cutoff switch and a small microwave for heating stuff up. Stashed in the storage area will be a propane camp stove for real meals.
Need to pick up some graph paper and sketch out some plans over the next couple months. The mad money savings need to recharge.
For the time being, a chunk of poly carpeting glued to 3/8" plywood cut to fit the floor and an air mattress will suffice.

First priority is the hitch and bike carrier.