In that situation it will be iffy...could be if you pull in the slides, set the heat at 65 or lower, cover all windows/windshield, your battery bank if fully charged--you may make it all night. It will also depend on how cold. If the temps are well below freezing all night long your system will need to run quite a bit. All motorhomes hold heat differently so until your try this you just won't know how conditions will be in your particular coach. If there will be wind and snow...that too will change the situation.
How many days will you be in the cold? On a long weekend--be sure to have a back-up tank with you just in case you run low. I'm guessing you will also be cooking and using the water heater on gas.
We've dry camped overnight running the furnace and a CPAP machine...we just about drained the batteries and needed to fire the genny very early. In cold weather you don't want to take your batteries down too low.
If at all possible do a test run before your trip in the driveway so you have a good idea how long your system will run without being recharged. It pays to know, not guess.
Newmar put the thermostat beside the dooron an outside wall. .. The coldest place in the MH. The furnace will be on and off constantly .. Should have been mounted on an inside wall near the centre. I'm looking at a way to change it.
2005 Newmar 34' Kountry Star, 8.1L W22, Blue Ox 10K, Honda Pilot, Bijon Shitzu (Sassy) dash dog, Two teenage boys..we get around ! Nine Provinces, Two Territories, 47 States, Northern Mexico... so far..
Our 1993 MH is quite well vented we learned one night at a swim met out of town parked on the side of the street.
The wind was up to about 30-40 MPH out of the north and the air temp was 16F. We all got in the bed but it was still cold. I wound up resting in the drivers seat because I lost the cover fight with the kids in part. I had the furnace, generator running for 1500 watt electric heater and even the engine running a lot of the time. While we have a working CO detector I do not permit myself to sleep with that much equipment running for sereral reason. Their team was not up until after lunch so I got some rest after the sun came up and it warmed up a bit.
We never plan to do those temps again. It was 32F last Sep in Yellowstone one morning but there was no wind so it was not bad at all.