From forum feedback, pop-up campers are not much lighter than solid walls?
Anyway, ditto on checking your rear axle capacity and go from there.
Enforcing GVWR can be tricky.
Years ago I drove F450, who at the time was registered under it own weight of 9000 lb.
Having small backhoe on it, I got pulled over by DOT officer, who read door sticker saying 15,000 lb, so he send me to DMV and in California at the time they required GCWR declaration, what gave big weight labels to be attached on sides of the cabin.
The 30,000 lb declaration cost me additional $450, what later went up to $600.