In my diesel, there is heat that goes through the basement area so the tanks will not freeze. We have heat pumps on the roof and propane heat in floor ducts.
I have a Newmar and it did very well when we were watching the house being built and had a 100 year snow storm go through the area. We had very cold temperatures for our area. We built an insulated box around the water filters and softener and hung a lamp in there. We insulated the hoses and dripped water at night when it was going to be below around 15 degrees at night. We made it through just fine but it took a lot of propane even though we were running two electric heaters.
There is a lot of information on the forums about how to set up an RV when it is cold. Personally, I would just head south.