My older brother and his wife traveled from MI to Alaska and back, sleeping in the shell atop their Ranger. No reason why it can't be done.
You can order a shell with screened side windows that open. Maybe you could get a top vent with a Maxx or Fantastic Fan, and carry a deep cycle battery to power it. Tons of ventilation that way. AC will be harder to manage; it might be possible to rig up a room air conditioner to poke out of a side window, but the unit with its support frame could eat up a lot of space.
I've had a series of travel trailers, but currently all I have is an empty-shell trailer that I use daily to haul merchandise for my work. I have decided to use this trailer to camp in, at least for a while. It has a 'people size' access door with a screened window, and 2 small screened windows on the sides. It won't have AC, a sink with running water, or a fancy looking interior, but I can have just about everything else I need. I can leave my cot and my zero gravity lounger set up in it, strap my bike to the wall, and still have plenty of room for bins full of camping stuff.
