I use ZEP on all of my TC fiberglass, plastic, and trim. The front of ours was oxidized the most so needed more coats. I've found no adverse effect. This is the same coating that's sold to re-new the look of old boats.
I've used the stripper to remove some where I got trash in it. It caused no adverse effects either.
A friend used all over his 90 something class B, plastic, paint, and fiberglass. It is easier and lasts longer than wax.
Try it on a small area first. If the camper is already oxidized, you really have nothing to loose. A coating is all you can do to help the looks of it.