First off welcome Brad, nice to have you aboard.
If you are comfortable with a mag mount antenna you could bond to the roof a suitable piece of steel (painted on all sides and edges, as an automobile) with mastic (Sikaflex 292) and or sealing pop rivets (often used on boats) onto which the mag mount will stick. This is a good way as if you should knock it on some low lying object it will depart without hurting the roof.
A wire antenna slung over a tree is popular as is a vertical on a tripod stand close to your camper.
You might get comments about antennas in the trees and bushes and on stands, but if it is mounted to your camper I do not see how you can be discriminated against, unless you cause interference with/for others camping nearby.
JIM