My experience has been that the default meaning of "camper" is a slide-in unit on the bed of a pickup truck......but there certainly aren't any hard and fast rules that I'm aware of.
Just to muddy the waters, and maybe it's a symptom of where one grows up, but I can't bring myself to use the term "camping" when it involves a Recreational Vehicle. "Camping" to me just always involved a backpack, a tent, and preferably a significant hike, an airplane drop-off, or some riverboating...or all of the above. If "it" involved driving somewhere before setting up a tent, it was "car camping".
Driving/towing/pulling a Recreational Vehicle to a spot (whether called a campground or not) is "RV'ng" to me and not "camping"...but I suspect I'm very much in the minority.
