Carolyn,
I've had a 1997 Xplorer 230XL since 2000 and live in Michigan. You are doing everything great. I remove the house batteries to inside and charge them every 2-3 months or so. I did just add LiFePo4 batteries so I'm not sure about them. I did not use my rv from Oct 2019 to April 2021 due to health issues. No problems. I do not leave it plugged in. I might run a portable charger out to the starter battery once in the winter.
You do not need to start it or move it.
I love my Xplorer. It has a few minor issues, but the engine is running great with 193,000 miles. Wish we were closer to get together.
Steve