Where I camp down here, there is far far less light than this. When I parked a bus in the sun at Xcalak I had a 24/7 generator and THREE roof airs going to keep interior temps in the 80's and humidity in the sixties. Maybe it's different up there, running a generator marathon style down here is a loser. Fuel, access to fuel, fuel cost make it ridiculous. Slow charging a battery bank is like barbecuing a steak one briquette at a time.
I had neighbor's kids make a palm frond and bamboo cocoon for the bus. For the shade. Solar works when it can work. Where it can work.