Winter camping - prevent freezing
April,
That's a tough question. I'm not familar with your camper so not sure if it has enough insulation for cold weather operation, etc., however, other than making sure you have a good furnace (with plenty of lp & extra tank(s)) I'd think the biggest concern would be the water system......fresh water, gray/black water, dumping when needed. Your gonna need some way to keep the water lines from freezing so I suggest you contact your dealership and talk to them about it. Might be as easy as putting some type of anti-freeze (not the liquid) type wrap on the lines that may have heat in the wrap. Not sure you will get mold/mildew in winter months....might be too cold for that, but you may get condensation on windows from heat inside vs outside. I might be tempted to put some of those moisture absorbers (I use it for my boat during winter storage) used in boats. You gonna shower in the camper also?
Maybe you ought to head South where it is warm while they are building your house.....

....just kidding.
There are some really knowledgable folks out there so hang in there and you'll probably get a lot better answer from them.
Good luck (by the way, hope you and your spouse get along real well since you'll be in really close quarters).