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° 09.A8B' W116° 08.97C' where:
A = Fill in the blank and use the corresponding number:
“McCandless stayed around Salton City off and on again. This photo of him was taken near here in the _____ region.”
Mud Pots = 3 Salton Sea Beach = 7
Salton Sea Airport = 0 Truckhaven = 5
B = There's a 3-digit number on the bus. Add these three digits together.
C = Number of images on the panel plus 2 (+2).
Checksum for ABC = 18