Sue, I do things a little differently.
I winterize my rig in early November and put it in the storage facility. Monthly, I get it out and drive it for at least an hour at highway speeds. I turn the coach battery system on, start the generator to exercise it, put a load on the system by turning on the heat strips on the AC (you can just plug in a small electric room heater if you don't have strips) and then off I go. I usually run up the highway to a town about 25 miles away, go in and have a burger (leaving the generator running on the RV) and then drive back to the storage facility. I have done this for more years and more winters than I care to remember.
I live in an area that can be very cold for a few days (single digits) at times and then be picture perfect and warm for a week and that pattern can continue for several months. If you live where it is cold for months at a time, you need to have a more aggressive plan for the batteries.