The setup Valence had is appealing. Those cargo truck beds are spacious. The close-up pics are good, they show just how much room there is. Adding an insulated layer under the existing canvas could help keep the heat in. Much like an insulated tipi. That truck/tool box could be used to secure my computer equipment and things that look pricy while in town getting supplies in the remote chance someone peeks in.
Can the canvas in good condition withstand 60-80MPH wind? It gets pretty windy anywhere near the Sierras. There may be a problem with the wind sucking the heat out too. I wouldn't know how to address that, need to keep the fingers warm to type and use the trackpad. But getting a cargo setup like that would keep me from going overboard initially and it would be mobile enough in the more open country.
As long as the cargo cover is lashed down tightly, and not put on backwards, IMO, it will survive 60-80 MPH winds just fine. My currently equipped cargo cover is not new and it has had some professional sewing to fix it (re-stitch windows and other repairs from damage by previous owner). I cruise my M35A2 at about 50 MPH on the interstate, so I'm sure it has seen well above 60 MPH wind and it shows no signs of further deterioration. I will admit that's only about 2000 miles of use in 3-4 years and it gets stored indoors.
As red pointed out, the problem with my setup in the bed is the low height due to the cargo cover. You are stooped over and your back quickly gets tired. It is plenty high when sitting down though. I left the tailgate down but folded the rear cargo cover flap down so there was about an 18" opening along the bed end (more than enough ventilation - cracking a window flap would have sufficed). As you can see, I had a small, single tank version of the Mr. Heater. That night, temperatures got down into the 40's and I started the heater more for fun than necessity. It quickly got too warm inside. I just threw the gear/cot arrangement together, a little different layout would give more open floor area. Also as red pointed out, an M939 series cargo has +2 additional feet of space in the front that you could setup for secure storage. The Knaack box in my bed is as big of a model that will still allow the troop seats to fold down, though it kind of blocks the seating at the front.
Anyway, it's a decent setup that lets the truck serve multiple purposes, but is labor and time intensive to gather/organize the necessary (and unnecessary lol) camping articles each time.
The 60-80 MPH winds will be more concern to actually getting to sleep (noise) and to the rest of the camp:
Camp fire, chairs, cooking area, bathroom/shower tent... etc
If I could have any "take-backsies" or "do overs", the #1 would be Power Steering. Fortunately, all the truck models that you're considering here have that covered. My truck, even with added air-assist steering, quickly wears out the elbows as the truck tries to turn at every rock on the trail. That said though, on sandy, well dug out trails with high sides, the truck literally steers itself. I mean, hands off the wheel steering as it rode and turned from rut to rut, or side berm to side berm - which was immensely entertaining.
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