There are many 5th wheels that have heated basements, tanks, and such. My former 2008 Keystone Everest did pretty good in the snow but it sure did suck down the propane to keep things warm. It was OK for a night or two but not more unless you have access to propane refill. Our current Voltage TH has also been in the snow and did well but it, too, sucked down the propane. Both trailers have heating for the tanks and water lines and electric fireplaces. But they all lack home-style insulation, which is the kicker.
2013 Chevy 3500HD CC dually
2014 Voltage 3600 toy hauler
2019 RZR 1000XP TRE