I advise to remove all 3 batteries, bring them home and store them inside where temps are controlled. I would not worry about starting up the rig in the winter either. People do that, but I really question the benefits. Others will chime in with opposing views to mine so you will have to decide for yourself.
When placing the motor home in storage....
- top off the main fuel tank
- completely drain the black and gray tanks, and also the sanicon by using the 3" poop drain cap
- completely drain, then put in the pink anti-freeze in the freash water system
- put 80psi in all tires to minimize ground contact
- cover all windows with sunshade material because using your regular shades just degrades them from the sun
- open all cabinet doors, fridge and freezer to circulate air better
- turn your dash board to max a/c to deter rodents from getting into the interior through that air iinlet
- place mouse/rat poison on the floor, just in-case
- don't leave any windows or roof vents open
- a full RV cover or tarp is not required, but never hurts
If you inspect it on rare occasion, bring the chassis battery with you. You might need to start the engine to heat up and dry out the interior of any dampness. But if it's well sealed and fairly dry, don't.
If you do run the engine, make sure the dangling RV battery cables are insulated.
Also run the generator.