I gather this is a motor home. So you have an on board Generator
This generator should be run under 1/2 load for at least 1/2 hour every month Storage or not it needs to be run. This keeps some components "Fresh" keeps slip rings polished and does other nice things... NOTE this is mostly for the benefit of the GENERATOR not the motor.
I installed two additional circuits 20 amp. 12ga wire 15/20 amp type outlets (Different color) for use with electric space heaters (I DO NOT recommend putting a 1500 watt heater on a standard RV outlet) this works out great.
IN your case I'd run the generator at least one hour once a month. Monitor battery SOC and if the voltage starts droppign too much. ADD more generator time to that run (Check voltage before you reconnect batteries before you start generator) Up to 4 hours if batteries really need it. In time you will fine tune the run time. Make sure gas tank is full before you park for the winter.