I would suggest not using a truck mounted type camper. Reason being if you need the truck to scout around, retrieve game, rescue another stuck truck or make a run to town you have to take down camp and that could leave your hunting partner without shelter. I would go with a pop up...not the best insulation wise but there are things you can do to help and make a difference if you don't mind doing some work. Plus many, especially new ones, have a heater, stove, sink two beds, more room to hang wet gear to dry store your clothing/gear etc.
I used to hunt out of a tent and it was never a big deal to be without any amenities, I backpacked in the winter many times and have been caught in my fair share of snowstorms doing so. But, as I get older I like a nice warm place to dry out and rest after hunting the mountains all day. PLUS a inside toilet is nice in the middle of the night when it's real cold. Some pop ups have a cassette toilet, we use an old 25' pull behind hard side camper now....
Darrell