Do not know what type of charging system you have for your batteries but my Newmar has what is call a BIRD System
that will charge the house batteries and when they are fully charged than it will charge the chassis battery, Intellitec has them for both the gas chassis and a DP chassis.
My coach is plugged into 120 all year long when at home and never had a dead battery on this coach in ten years or for that matter any of my Newmars.
The chassis battery is ten years old and house batteries were changed out to 2 AGM's about 4 years ago.
Once you have changed the oil for winter and winterized the coach just leave it alone until spring does no good to start up for 1/2 hour its better if you take it for long drive.
My coach has not started since Oct and will not move until March.
Store the tires on sheets of plywood to get off ground and say goodnight.
Welcome to irv2.