It's a year-round resident of Scottsdale. I have an electronic thermometer in the coach, and it has hit 136 degrees in there this summer. It only goes on camping trips about 3-4 times a year. In the meantime, I drive it in a 4 mile loop around my house once a month to keep everything limber. Also it is an 82 with a carbureted non-catalytic 454. I put in 10 gallons of av-gas every spring because it doesn't go bad like the oxygenated crap we have here in phx. Thanks to the avgas, it has gone 18 years without a single carb problem.
I enlarged the battery box in '96 to hold 1 engine batt and 2 deep cycle coach batts. I put in a 200 amp relay that I activate with a switch on the dash to connect the engine and coach batts , so I can charge the coach with the alternator or charge the engine batt with the generator/12v coach power supply. Plus I can bring in the coach batts to start the engine if needed. I have a separate trickle charger for the engine and coach batts.
I went through a lot of batteries til I got things figured out. The secret for me was to NOT leave it on the trickle chargers past April. Battery chemistry changes with temp - if it is 30° you need 14.5 volts to charge. At 120° 13.2 volts will charge. Cheap maintenance chargers (even Battery Tenders) go into a float mode of 13.6-13.9 volts, which is too high in the AZ summer. I kept cooking batteries dry and ruining them.
Expensive inverters have the most sophisticated chargers built in, and the best ones track temperature for a proper charge and float. I bought a 1500 watt Trace inverter probably 8 years ago and never put it in. Dang it - I curse my laziness.. So what worked for the 9 year battery was to manually plug in an extension cord to the rv once a week for a full day to let the maintenance chargers do their thing. Sometimes I forget and let it go 2 weeks, other times I leave it plugged in for a full week. Somehow it all worked out.
Ideally I will put in the Trace inverter and have all the advantages of a real inverter, including proper charging. Next best would be to put the extension cord on a 1 week wall timer, and set it to come on one day a week. Or likely I will just try to remember to keep plugging it in every week.