1-Keep the front enclosed, use it to put your bed, shower, bathroom, closet, flat screen TV, a few windows and a vent with a powerful fan.
2-Keep the back as a living room, close the sides, put nice big windows on sides, carpet/rugs on floor, cut open to put a door or a metal security door so you can enter from the front and climb in to the passenger seats when needed.
3-put as much solar panels on roof, vents with fans, and figure a way to put a solid platform to convert it into a sitting area for you or a few friends or you and your significant other put a few pillows and warm blanket with a bottle of champagne and watch the stars. Just make sure you have something to avoid falling over the sides if you get to crazy up there!
4-Build a foldable set of rails on the deck and even you leave/on the road you can fold them down, attach them to sides bottom part of the living room area till you get to your next destination.
5-install 2 foldable doors on the back. One door folds down to turn into a deck/porch with foldable rails and put LED lights. The second one goes on top to open up and you have instant roof/shade, put LED lights and put a few fluffy chairs for you or whoever... guests. When you go to sleep, close em up and you have security. You can also put a bug screen all around and you have an extra little room and keep the mosquitos out in the Summer yet enjoying the outdoors with a cold cold big glass of lemonade.
6-install a door on both sides of the box so you have 2 ways to get out in case you park in an odd spot and wish your door was on the other side, you have 2. Dn't forget the awning.
7-If your like me, you can option to have a killer kitchen in your living room area also. Dn't forget a nice surround sound setup and a recliner and a fluffy bed for "Fido." Keep it clean and leave very little outside things to avoid it looking like a pack rat, it helps to deter attention from cops harassing you. You don't want to look like Jethro's pickup and draw unwanted attention.