The cache is NOT at the above coordinates!
This is an in-the-field puzzle. You'll need to go to the panel at the posted coords and gather the needed information to get the coords to the final location.
Final location is at N33° 10.09A' W116° 09.0BC' where:
A = Number of people in the photo on the far right (smoke in the background) minus 4 (-4).
B = Number of images on the panel plus 2 (+2).
C = Fill in the blank and use the corresponding number:
“Many nearby park landmarks are easily recognizable throughout the film, especially _____, as can be see in the backgrounds below.”
Blowsand = 5 Pumpkin Patch = 0
Devil's Slide = 8 Gas Domes = 2
Checksum for ABC = 15