Curtis, if you have shore power, get an electric heater in addition to your furnace/gas heater, will help with the internal cabin temps... then assess your basement components and how you need to insulate or provide heat to those areas.
Assuming you have a heated water hose.. for your water intake if your are using camp ground water source ... some camp grounds require it, but best to use either way...can find on amazon with search...
If your basement areas do not have heated vents, most on threads recommend skirting to keep the under carriage temps somewhat reasonable.
There are many threads and ideas in forums as well for how to deal with low temps.
We use a heated water hose, have basement heated vent, and insulation between
the under skirt and belly of our Fifth Wheel...and didn't have an issue this past March with sub 32 deg temps....didn't get to 0 though.
2019 NP 383FKWS
2019 RAM 3500 DRW