Leo Carillo has a few campsites but the one we went to was along the beach. RV's are lined up along the beach so you are super close to your neighbor. However, when the sun goes down and if you sit in your tent or Camper-van, you don't really notice the other people and you can take in the starry sky with the sound of the ocean (which is AMAZING). If you want a peaceful camping experience you just have to hope for quiet neighbors. Also arrive early for a campsite or book ahead. We got lucky and arrived before a lot of other campers but heard it can be hard to get a campsite here.
Great campground, sites aren't too close to each other. We went during spring break and it wasn't as busy as expected. (Maybe we had a different Spring break than everyone?!) It was warm during the day and SUPER cold at night so be prepared with a heavy sleeping bag!