This cache may be tricky to find but is probably trickier to retrieve. I find that a pair of keys works well to grab it, but a Leatherman or similar multitool should work great, or perhaps even twigs used like chopsticks.
Signal reception may be tricky because of the structure. Try without the hint but if you're frustrated it's there to narrow down the search.
Parking is adjacent, around N37 11.282' W121 46.551' to the right of the boat ramp, at the north entrance to the park. There is a park fee (county park pass works though) and there's no free legal parking anywhere remotely close, unfortunately. Please obey the various park rules and hours.