My go to recommendation is the California Science Center in Los Angeles. It's a science museum with a little bit of everything, including a smallish aquarium. The big feature is the Space Shuttle Endeavour.
There is always the beach. Huntington Beach has a Ruby's Diner on the end of the pier. Our kids loved eating there. The Santa Ana Zoo is a quiet, little zoo. Nicely inexpensive. Lots of kids love the dinners at Medieval Times in Buena Park.
My go to recommendation is the California Science Center in Los Angeles. It's a science museum with a little bit of everything, including a smallish aquarium. The big feature is the Space Shuttle Endeavour.
My son is 4, and our trip there in January sparked his obsession with space shuttles. Then we had to go back in March because he lost his beloved Endeavour that he carried everywhere with him. That trip sparked his obsession with the external fuel tank. It's a really great museum.
My son loves dinosaurs, so last year, we went to the Los Angeles Natural History Museum. It was a little bit of a drive from there. So we did that after our last day, and then our parties went their separate ways after that.
I still remember the trip we took to Legoland after Disney years and years ago, sister and I were 5 and 7 at the time and we loved it. I think it's about an hour drive depending on traffic