In no way, shape or form should a rocket stove ( home made , tin can , cooking stove, or symtore bought version) be burned INSIDE a van, or any other e.closed area. No ned to reinvent the wheel here, either. The calculations have been done, and 1800 watts of battery bank would be to heavy and bulky to move around, unless you happen to be converting a large box van. Solar IS possible, but again, cost and size are limmiting , if not prohibitive , and thats just for the small 5000 btu window units, let alone a 10 or 13000 btu rooftop model. If you get a brand new roof unit installed at a rv dealer, it will be around a gran, or even more. A Honda 2000 generator will be around another grand, so not sure where $3k came from, but craigslist and ebay are only a fee keystrokes away. Its possible to have both for under a thousand. Other than that, think about some of the above suggestions involving shore power, moving with the seasons, parking in the shade, staying out of the vehicle during the heat of the day, etc. I dont have ac in the bus, not even dash ac, and i live in alabama. Painting the roof white and adding a roof vent lowered the inside temp by 20 degrees on the hottest days. It used to get 135 in there on a 100
Degree day. I can sit in the shade for a while untill it cools down some.