Scammed indeed! I found a 2" duct that at least put some warm air into the underbelly but came out BEHIND the rear gray water tank so not going forward very far. I ended up pulling the underbelly plastic off by 6 sections (about 30' of it) and adding insulation I had left over from shop insulation add. Added panels to inside of frame rail and a sheet of it across under the plastic I put back up. Then ducted the 2" into a PVC pipe that shoots it forward. I did not add heated pads to the tanks but could later. Dey ain't cheap and I don't think we will be out in that extreme temps, but one never knows. I still need to seal the seams and perimeter with EternaBond tape that came last Friday. It is upper 30s and rain turning to snow later so NOT going out there today. But I did finish winterizing today before the 20s hit tonight. It took 3 gallons to see pink at all faucets and then added some more to the drains.
Oh and I also used window/door foam in a can to fill the holes in the floor where the pipes and electric come through. And used pipe insulation on all the pipes and tie wraps to hold in place.