If you have a smooth area to work with a razor blade works well. You take a new razor blade and scrap it back and forth across concrete 10 times or so. That dulls it enough to keep it from digging into the paint. It is a trick car detailers use to remove pin stripe decals or any other decal. I tried this to remove the 4x4 sticker off my 6 month old truck and it worked well. If you have an aluminum sided camper you will have to be careful of the ridges. I would think a hair dryer and a dull razor blade would work pretty well to remove any decal.
TV - 2011 Chevy 2500hd CC SB 4x4 6.0l
TT- 2012 Jay Flight 32bhds- Elite, Thermal, Technology, Hide a Bed, Outdoor Kitchen, Ladder, Power Awning