Camping in 12 degree weather, Help

Leaving Saturday from Tampa to Lansing, Michigan. Checking weather and they said it might get to 12 degrees while we are up there. We will be gone for two weeks. Any suggestions. I want to stay in the camper everynight, but will we freeze to death? We stay at different houses (all family) and can go in, but prefer to stay in the TM. Read post about winterizing, but hope it will be warm enough during the day while we are traveling not to freeze and will have heaters going at night to prevent freezing. We have the furnace, a Mr. Heater, and a couple of electric heaters. Any suggestions would be appreciated.

Never camped below 25 degrees before. If we hit snow, we are going home. John.