Hi,
Here is a short list of items that need to be dealt with if planning for the possible -40 weather often seen in Montana.
Fridge anti freeze protection
Outside shower (if any) needs to be insulated
Compartment doors insulation beefed up.
Waste tanks and valves may need additional heating
Consider skirting the entire unit and adding a heater underneath
Add an electric mattress pad heater
Replace the 120 volt outlets where heaters will be used. I prefer oil filled heaters because their surface temperatures are much lower. Walmart sells some 1/2 size units that can be tucked away in spaces that are otherwise essentially wasted space.
Add a second shore power cord that can be used for providing electric heat. (I have the OEM 30, a 20, and a 15 amp).
Arrange rental of a 100 pound external tank and a extend-a-stay fitting to allow it to be used. The on board tank should be kept "in reserve" and in extreme cold may only last 72 hours.
You really have little time left before the cold moves in for the fall. Last December it was -36 C (-33 F).
