need some expert advise for newbies

Sell the house now and move into the motorhome. Why wait until January with the weather and slower home sales? You stated you'll go to the northeast in January so you'll only be staying in the motorhome in about two months of winter - Nov/Dec. You'll be going through a lot of propane with heat and you might consider a catalytic propane heater that is much more efficient than the furnace. Buy silver foil insulation for your windows at Home Depot. Get a heavy down comforter for sleeping. Fill your water tank and run the water off that rather than trying to keep the outside hose thawed. Don't keep your dump valves open. In fact, it's best to store your sewer hose until you need to dump so it doesn't get brittle in freezing weather. Wait until your tanks are full to dump. It's very doable for a couple months. Good luck!

P.S. Perhaps the moderator will move your post over to the Full-timers section where some experienced winter campers can help!