So it was a lot more than just a day on my back. I think more like 3-4 days. Fortunately I used my nice creeper from my auto shop. I was buzzing around rolling and using the undercarriage as hand holds to maneuver. It made moving around so much easier- almost fun except for reaching up and straining my neck and upper back. But it is all worth it. Yesterday it got close to 70 and I checked inside camper this morning. It was 39 F outside and 44 inside. The heat was not on last night and I can still see daylight around the slider seals which are still to be fixed. It just seems more quiet and warmer inside. I don't think that is just my imagination. If it were, I would be hearing things that go bump and seeing things flit at the edges of my vision.
So overall the time spent was worth it. Eventually I will look more into the ceiling and see if it is possible to add some there since that will be most effective at stopping heat escape. I replaced the wimpy bathroom fan with one that can go 3 speeds forward and 2 reverse (I forget the brand). When I had the trim pulled I remember seeing open space. And of course running down the middle was a single roll in fiberglass insulation- of course all open around it. I think I might be able to blow insulation in the open areas. I have access via trim panels at about equal spacing along roof with vents, skylites, and AC unit. Then working on a design to put another layer over the windows. I can make in inner storm to fit over the single pane windows if we are out in the colder weather. It may not be worth the effort but we will see. It is worth exploring. I suspect the frames are aluminum and not magnetic. I am a woodworker so making frames with magnets in the frame would have worked nicely. Hmmmm .... we shall see. One thing at a time. But successful true Extreme Weather modifications. I may try to add booster fans in the floor heat registers to pull the heat for better distribution. I can still easily get under the floor and have some 12 VDC computer fans left over from 41+ years in IT. It might not be worth that amount of work. It is easy to get carried away.