The Golden Park pass is good for all government owned parks. Although Lake Shasta Caverns is a National Natural Landmark, it is actually a privately owned attraction and does not honor state or federal passes.
This is a small park. Fun to see maybe a couple times. Yosemite, as mentioned by Mayur, definitely has a lot more things to see and do!
I would suggest Yosemite if you can choose just one park.
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