Thanks Oldtymeflyr - It looks like you're just down the hill from me...I'm in the foothills above Golden.
Super helpful information, thanks. I actually bought the same solar panel (Windy Nation, z clips) through Amazon. When I drilled the pilot hole to route the cables, it looked like the roof composition was only very thin veneer wood, over a foam core, which made me nervous running anything that wouldn't be a self anchoring screw.
My camper has a boat rack type thing on the roof, with three raised bar sections. I am planning to put the panel between the middle and rear rack sections, essentially right over the battery bank. I've already mounted the controller and have wired it into the battery bank, so the panel mounting and wiring are my last steps.
I did pick up some Dicor lap sealant, so I'm all set there...just need to figure out the particulars of actually mounting it. I'll take another look at the roof composition and depth, and will check out those screws that you've mentioned.