In a Seneca, with their “enclosed and heater basement” (just typing that makes me laugh, you will only be heating areas with water lines to 5 degrees above ambient temperatures. This is the best case scenario and was verified by a remote temp sensing system I installed. Therefore, you cannot count on your furnace to keep the water lines safe.
Then, on your drive, which may be in cold temps, you will have several considerations to make. Will you run with LP on; many people here are on either side of that discussion. Will you continue to run these electric space heaters during your drive, understanding that you will need to run the gen and make certain they do not tip over (see Steve’s solution), or come in contact with flammable components during the journey.
That being said, several of us have taken measures to operate these units in severely cold climates they were never designed to do. I have wrapped many lines in heat tape and insulation to keep myself safe (good to 4 degrees). I think there may be complete limitations to how cold you can go, but I will find out this winter in Illinois.
What are you using for a setup for your compressed air winterizing system. I currently need 8 gallons of antifreeze (I know, I am doing something wrong here) to winterize and this may be a good solution.
Ryan, Maria, and Riley & Myla (Golden Retrievers)
2018 Jayco Seneca 37TS