[travelin texans]

First off the "extreme thermal package" is only a sales gimmick & not any better than any other RV in "extreme thermal" conditions.
Agree, get the heated water hose or wrap yours with heat tape & insulate it whichever you use.
Be sure to run your furnace as your RV may have a duct to the underbelly to aid in keeping water line & tanks from freezing.
Contact your local LP distributor & have them set a 100 lb tank, or larger, at your RV & have them keep it full, this will save you from getting smaller tanks filled every 4 to 5 days.
If leaving your sewer hose connected you'll want to find some way to insulate it & not leave any valves open, only drain when necessary. Be sure it has enough slope that it drains completely.
Others will chime in with things I know I've missed.
Good luck & stay warm.