At the posted coordinates you find yourself in the center of the former Douglas Aircraft Company facility. The cache is not hidden here.
Donald W. Douglas opened the Long Beach facility on the eve of World War II, on October 22, 1941. It was a most modern factory and the first "blackout" plant to be established in the United States. This "blackout" factory was designed to be invisible at night, windowless, air-conditioned (a first), camouflaged as a suburban housing tract, and provided with bomb shelters for its thousands of workers. The picture below was taken a few days earlier and it shows the Giant Bomber B-19 in Flight. Thousands were here to celebrate the opening of the new facility.
IF YOU WERE STANDING HERE ON OCTOBER 17, 1941
THIS IS WHAT YOU WOULD HAVE SEEN
Update 3/23/2019: I found a video of the B-19 flyover on Youtube. Click HERE to view it.
Somewhere around here, there is a plaque dedicated to the event shown in the picture. Find that plaque, and go stand as close to that plaque as you can. NOTE: plaque is not attached to the walls of the hangar.
From where you stand, project the wingspan of a Douglas B-19 at a forward azimuth of 315.929143. That will take you to the final. All stages are wheelchair accessible.