Class A Fulltimer freeze concerns

If really want to be safe, go to tractor supply and buy a freeze cube. They plug in a electrical socket and at 35 degrees they will turn on a heater and off at and 45 degrees. Used for animal water tanks. Go to walmart and purchase a 400 watt personal heater. Put this in your wet bay and worries are over.

Within the motorhome, there shouldn't be problems, as others have said.

You do need to disconnect the water supply hose in freezing weather lest the water spigot and the water inlet freeze and split. (Most hoses are flexible enough to withstand freezing water in the hose proper, but brass and plastic fittings have rather less give.) There are heated hoses etc. to work around this, but I don't think they'd be worth it for you when you won't be spending a good deal of time in freezing conditions.

It wouldn't hurt to stow the sewer hose as well in freezing conditions.

It's good to keep a watchful eye on low temps. I'll also reiterate that Newmar's are so well insulated it shouldn't be an issue. For your own piece of mind why not get a wireless thermometer, place in basement, & you can see for yourself how warm it is staying.

I never have had frozen water lines. If I am in a freezing area for any great period I put a heat tape on the waterline from the spigot up to the motorhome.You may call me if you have any questions. Be happy to share with you.

Newmars are well insulated; as long as you use your furnace you should have no problems.