I would encourage you to search the forum, especially when you are in a pinch (ie, looking for info during off hours). There is a lot of discussion on this topic with lots of different perspectives.
We frequently get into the 20s and teens during winter camping. Our trailer has a sealed/enclosed underbelly but does not have a “Polar Package”. Tanks are not heated. The dealer’s only recommendation on sub-freezing camping was to run the furnace. The ducts will keep plumbing from freezing. Our experience has been;
-Hose bib at the campsite will likely freeze (ie, no water available). I fill the fresh water tank the day before and disconnect the hose and filter and store it (as mentioned above). We use the pump/fresh water tank for water until the hose bib thaws, then reconnect to city water.
-fresh water tank and Waste tank valves that are exposed will freeze. This is a problem when your tanks are full or you are ready to packup and leave (ie, want to dump before getting on the road). We try to dump before it freezes. I used a blow dryer for about 20 min on it once when it was 17 deg the morning we were leaving. It worked.
-If you are storing liquids outside, put them in a cooler to prevent from freezing if necessary.
-We have found the best solution for us is to have an electric oil filled heater ($30 wallyworld). It provides excellent comfort day and night in the trailer. We use it anytime we expect to be cold. We turn the furnace down to 60 deg, so it also saves on propane usage while still keeping underbelly stuff warm.
We can manage ok as long as it thaws the next day. I am not prepared to camp more than a day or two before a thaw….we like our creature comforts ;-)
Other than that, enjoy the great outdoors on these crisp days. It is usually quiet and peaceful when it is this cold.
2016 RAM 3500 6.7L DRW
2018 Chaparral 360IBL, Andersen Ultimate II hitch