1) your in a trailer so you should have zero windchill factor in the treiler.
2) Just bring a few comforters, quilts etc... and if you need them use them. You really have no limit to what your caring if your bring a trailer.
3) Get some kind of 12volt heater and you can use it to warm the trailer up a few degrees, or a 12/120 inverter and use a standared home heater.
4) Even in negative degrees out side in a trailer you should be find.

Cheers