Bill has addressed some of the issues in his post. A lot of folks, us included, spend a lot of time in the cold weather with very little issue. A lot of the problems or lack thereof depend on how your rig is set up, especially at the water bay.
We have successfully dripped water down to 20 degrees without issue, although depending on how the water spigot is insulated, it could freeze first. Inside the coach, we have used auxiliary heaters and done just fine. Propane use is much higher under those circumstances, so it just depends on how easy it is where you are to refuel your propane.
Parking where you have good sun during the day helps immensely, believe it or not, because you can use your windshield to help transfer heat. You might be surprised at how effective that is. At night, that's a whole 'nuther story of electric mattress pads, or blankets, or little heaters, or down comforters. Not having to boondock and use a generator is a better solution to me, personally.
On the road through sub freezing temps, however, is another issue, and we avoid that. You COULD have some problems there with the cold air as you drive, so that might be a limiting factor on where and how you go. We have waited for weather to improve for just that reason if we are moving in the cold season.
If you can stay out of the northern tier of states at that time, generally speaking, I would think you would be fine. January and February, probably not so much.
Just another perspective from our personal experience. 8)
Kim