I'm from L.A. and visit frequently. I had never been to the Santa Monica mountains before but my partner and I decided to hike through one afternoon. We headed toward the swimming hole there. We got there and it was super crowded and the water was pretty gross so we decided to hike to more secluded areas. There are some pretty cool views all around and a bunch of different trails. We loved it. There's a visitor station you can stop at ahead of time to get info on where to go and what to see and to grab a map. Definitely recommend stopping here ahead of time.