We headed out of the cold in MN in January, and unfortunately came back to below zero temps last week (don't ask, long story, but we WON'T be returning when it's that cold next year:)
On the way down we left the 5er winterized, turned the fridge on, and set heat at ~50deg. Loaded up food etc, and hit the road. Did a long day to mid-Kansas where we dewinterized. After that it was normal ~cold travel for a couple days with fresh water tank full and head left on around 55 when traveling and turned up some when we got in.
On the way back up we kind of did the reverse. Drove to Chanute KS where we winterized, and then left heat and fridge on at 50/55 while we drove home to 0deg weather where we emptied stuff out and asked ourselves why we came back so soon!
Good luck, safe travels.
Ron