I keep the shower and chem toilet outside. Plumbed a heat exchanger into heater hoses and have hot water on demand. Uses a 12v pump and heats a 5 gallon bucket to too hot in a couple minutes. I use a bilge pump in the bucket once it's to desirable shower temp, plumbed through PVC and a shower head.
You have/keeping the rear benches and storage within? I have LOTS of tools and parts stored in those suckers. When I put the humvee Gypsy rack on top, I'm going to do a couple things: weld a pipe receiver in the center to put a pole which will have my 35' parachute on top- then extendable horizontal outriggers will extend out in 4 directions to hold the 'chute up, effectively shading the whole truck and surrounding area. Keeping cool and sun off the metal in the desert makes for comfortable camping. Can hang a shower/toilet curtain (if the girlfriend's camping with) off one of these too.
Instead of a shelf in the cab, I made this storage/table setup. Posted pix a few years back....
I use dual Jamar line lock for e-brakes- plumbed from the master cylinder to under the dash.

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