One of the reasons I got a Class B was because it was the biggest I could keep in my driveway at my last place.
We moved into this house last year and put in a gravel area next to my carport for my van. It stays there all winter with a cover on and under one of those Costco 20' car shelters that I raised up a bit. I have photos here:
$12 per month sounds very reasonable to me. We probably got down to about -6 C.
I use RV antifreeze in my tanks, pipes & traps. I keep the house batteries and the chassis battery on BatteryMINDers.
I haven't had any mice show up but it is a very common problem. Here's an article by Mark Polk: