Winter RV camping

We are first year, full time RVer's here in Colorado and have made it through one winter without any serious issues. With that in mind I want to reduce both my cooling and heating costs. I have found that the ceiling and floor currently are warm to the touch. With temps in the 80's to the 90's I think I need to do some extra insulating now, obviously before winter. By insulating now I would also decrease potential cooling costs. My concern or question is this; there is approximately 3 inches between the ceiling and roof joists, currently with only approximately 1 inch of fiberglass insulation. I believe this dead space could either 1) be heated in summer or 2) be cooled in winter. In theory this hotter or colder temperature could be transferred into the living area. How can I put more insulation in the ceiling, without tearing the whole thing apart? I briefly considered using expanding foam; however, I don’t want any issues with a bulging ceiling or roof, and I would not be able to spread the foam out over a large area. I also have considered using the holes for ceiling lights to blow in insulation. These holes are about 1 ½ inches in diameter and are about 4 to 6 feet apart. I have talked with a couple of neighbors and a couple of RV stores about this and nobody has any ideas on how to accomplish this. The local DIY stores don’t have any suggestions either. The floor I am not that concerned about at this time. Sometime soon I will be installing R-Tech Foam Insulation, and covering with carpet to look more aesthetic. Does anybody have any ideas about the ceiling?