You crossed a whole lot of contour lines. The climb ought to be a lot more.
Seven or so? Five-foot contours or not, that USGS map looks totally weird compared to what I'm seeing out there.
Seventeen hang gliders? No humans.
I think you missed one (and I don't mean the tow plane).
Looks like satellite imagery got updated, because now I see none. Well, arguably one, I guess, the very tired one on permanent display at the entrance, but it's far from airworthy.