Catalina Island is really taking flying destinations to a new level. It's a short trip from either LA or San Diego area. I try to stay high on the way to the island and keep an eye on the boats just in case you have to ditch. The airport is a little tricky as sits on top of a mesa. Fly with your CFI if it's your first time or check YouTube for some good information.
Once you land, go to the tower and pay $25 for landing and for the bus ticket to the town. During summer you should reserve the bus before coming as otherwise there probably won't be available seats. There is a cafe on the field. The bus trip is about 20 min and there is a good chance you will see buffalo on the way. There are plenty of restaurants in Avalon. You can also go to the beach club which is about 15 min walk. There you can enjoy the beach, food and different water activities.
Landing fee is $25 + $32 bus round trip to Avalon. Camping: you need to join their club for $150 / year.