The problem with an RV is they are built to be light weight to drive on the highway. They have insulation, but not near enough for a Montana winter. What that likely means is your propane heater will come on and not shut off for six months! Or if it does shut off, it will be back on in less than ten minutes because that's all it would take for all the heat in the motorhome to leave.
Looks like you got a 41 footer so I'm assuming you have two heaters. That's a good thing for cold weather. At least if one goes down you still have the other. Will the park allow you to use electric heat too? My preferred way to heat the motorhome would be with electric but it sounds like the park may not let you do that. Either way it's going to cost a lot of money to stay warm.