Lightweight and Air Conditioning don't mix well.
The exception is an expensive generator assist inverter like a new Magnum and a decent bank of batteries. Then you can size the generator to air conditioning run wattage rather than air conditioner start wattage.
Even when diesel was 15 cents a gallon here my Yamaha diesel ate 12 gallons a day 24 hours, three dollars X 30 = 90 dollars a month not counting generator wear and logistics of getting fuel, changing oil and filters. My bus soon acquired a window 5K unit and 1 cylinder diesel alternator setup powering things through the inverter.
Diesel is heavy, loud, most efficient, PITA dirty oil change, gasoline is the cheapest to buy medium maintenance, LPG is not cheap to convert fuel is a PITA to obtain, maintenance is a snap, and economy isn't the greatest.
