Personally I wouldn't use the steppir unless I were camping in areas of solitude/remote isolation and then I would carry the antenna (somehow) to tripod install it away from the coach with proper radials.
Mouting on the bumper? How would you lay it down for transport.
The steppir costs as much as a screwdriver and with it you will be on the forefront of experimenting and fiddling when others are operating. Perhaps that's what you like to do.
Several here shoot a wire up into a tree with very satisfactory results. Of course if you are a desert camper, good luck with that.
JIM
