Once upon a time, in an earlier chapter of my life, I lived in a house trailer. Not hard to get a little heat to warm the inside, but underneath seemed to freeze. We used the dark gray foam tubes with the slit to push onto all the pipes. Used heat tape too. Best thing to do is keep all the cold air out with whatever skirting you can get. We replaced tin with plywood. Straw bales around the skirting insulated good too. I guess if you don't want to look too redneck, you could put the bales inside the skirting. Better to look redneck than have frozen pipes though. Praying for your pipes, @Mother Hen.
There's heat tape around the pipes that go to the bathroom. Was told never had problem with hot water freezing in the kitchen yet earlier this year during the winter the kitchen started freezing.
Here in little bit I've got to dress really warm and go out and use the hair dryer under the trailer.
There's a slight issue - that side of the trailer has pieces of tin for skirting and because I was never shown how to get under there I didn't attempt it.