I have a 2011 Montana Mountaineer 326RLT. It has a heated underbelly. If it's above freezing in the day, connect your city water hose and fill your fresh tank. Then turn the city water off at the faucet. Disconnect your fresh water hose from the RV, drain the hose and stowe it if you don't want it frozen when you want to use it again.
If your RV is winterized, leave it that way till you get to where you are going. If you are not winterized and are traveling in freezing temps, your pump and lines will freeze. Mine did in 20+ temps so I had to stop every hour and run the furnace for about 15 minutes to keep the water pump thawed. If temps are freezing when you return home, winterize or blow out the lines before the return trip.
Here is a link to the brochure for the 2011 Montana Mountaineer. On the Options page under STANDARDS it says "Fully Enclosed and Heated Underelly".
https://library.rvusa.com/brochure/2...r_Brochure.pdf
At night when it is the coldest, open your cabinet doors to your washer/dryer so those pipes get some heat. If you have a fireplace, run it to help suplement the heat. But if the fireplace keeps the temps too high so that the furnace doesn't run - remember that the fireplace heats the area it is in, but if the furnace is not running then the underbelly is not getting any heat.
You'll do fine. Surprisingly when the furnace is keeping the RV warm the culprit is moisture inside the RV, especially inside closets and cabinets where there is no air movement. This is more of an issue with longterm RV'ing.