X2.
I've always identified the differences as:
Campers - those like above who use the RV for the purpose of camping, being a part of the outdoors, and getting away from technology, etc.
RVers - these are the folks who use their RV to travel and sightsee. They may visit national parks, etc., but their purpose is to "see" rather than to "camp".
Lifers - these are the folks who full-time, snowbird, part-time, etc. They are using the RV as a home. They may or may not stay in one place.
Now may be some cross-over between groups, but if asked, the most important factors will be in terms of their main category. For example, a Lifer may put importance on campfires, etc., but their most important factor is that the RV is their house.