As others have indicated, the best bet may to find an RV park when you arrive in December that has storage on-site (then move the RV into storage and take it back to your site when you return), or just leave the RV parked on your spot when you are away if the price isn't excessive.
We just left our RV on our site In Borrego Springs when we did a trip over to Hawaii but it wasn't as long as a month, if you are away just over Christmas you may want to consider doing the same thing, maybe a bit more expensive but less hassle (and you don't have to worry about a cold snap if you have it plugged in).