The important thing is to not let the batteries freeze. In more northern areas, this means keeping a good charge on all batteries. I'm surprised that you don't already have solar, but that would be the ideal solution to keep chassis and house batteries up at all times. I don't think temps in your area would get low enough to freeze a battery.
At the very least, bring the chassis batteries into a garage and throw a charge on them before putting them back into the coach in the spring. This will get your motor running and the engine alternator will put enough of a charge on the house batteries to start the genny.