Humidity is the biggest problem you have to deal with, fulltiming you will probably have to add a portable dehumidifier.
We manage by using the bathroom vent constantly running on low and mopping excess humidity off the windows, but that's for short term camping.
You will want to use a heated hose on the water supply and ensure the tanks are heated, some campers it's electrical heaters and some it's just spill air into the belly.
A full skirt will help to reduce the heating bills and give you some place to create storage. Personally I would go with a 2x wall with added insulation, but even just a vinyl skirt will help.
When I was a kid I was going nowhere fast, now I'm an old man I'm going everywhere slow.