I’m trying to find a place to go in the Los Angeles area (or within an hour or two drive from the city/suburbs) where you can go both caving (preferably spelunking or somewhere with a decent amount of adventure/difficulty) and then also go to the beach without a great deal of travel. Are there any locations, or is there anywhere along the California coast that would offer the cave/beach opportunities?
This looks like a job for GeographyMan!
Most caves are formed by water flowing through rock. In case you haven’t noticed, we don’t get much rain here, so we don’t have a lot of lakes, rivers, etc. We especially don’t have underwater rivers, which is what forms caves.
So, in a word, the answer is "no".