HI,
I am guessing that the Mesa location means that you need to run the A/C at night? That is sad. . If it was just to recharge the batteries, then solar panels will work great, but they do not make enough power to run the A/C overnight.
A Honda RV generator that is water cooled might help out a lot. But it is expensive, and you can sell the Onan for about $1,000 - $2,000?
The mechanic at my work had a 200 - 300 amp 12 volt charger that ran on a Bring and Stratton lawnmower size engine. He put on a muffler that should be mounted on a riding lawn mower, and it got really quiet! Yet it still is a air cooled motor, with a big fan blowing air across the engine with all it's internal vibrations. . .\
Mayberrys.com They sell Honda generators. A pair of 47 pound Honda 2000 generators can run the A/C when combined, and only make about 50 Db.
SunElec.com sells solar panels for a great price!
Fred.