On a beautiful day, Catalina Island -- one of the 8 Channel Islands in Southern California -- is gorgeous. About 22 miles southwest of LA, the port of Avalon resembles 
the Italian coast, the hills suggest the high desert, the atmosphere feels like Key West, and the wildlife -- well, besides swordfish and dolphins, delivered American Bison! This is the height of the easy-going Southern California culture, but you basically go there to take advantage of nature -- land or water. The town of Avalon is quaint but shopping is your basic touristy variety. And the beach is just a small slip of overcrowded sand. But feeling like you're really away from it all comes in part from the absence of 
cars on the island and the many things to do in the back country. Only 800 cars are allowed by permit only for permanent residents -- and most people (including 2000 residents and all tourists) travel by golf cart, bike, or small open-air tour buses and four-wheel-drive vehicles. (Golf carts aren't permitted in the interior.)
We left LA from Marina del Rey on the West Side, but the two-hour hydrofoil ride was almost double the length of ferries leaving Long Beach, San Pedro, and Orange County. That made an arduous start to the day, since the Pacific Ocean has major swells however you cross and Southern California's morning marine later is cool as well. Advice -- take the Catalina Express (about 1 hour) or the shortest ferry trip (or plane or helicopter) possible.
If you're going for the day, pack a bag and travel light. You can rent one of the 200 golf carts available for getting around. Plan to spend part of the day on a tour and part of it taking advantage of the water sports in and around Avalon -- snorkeling, diving, kayaking, and boat tours. The water is clear and rich in blues and aquamarine. This is an active place, not for the faint-hearted. If you stay overnight, arrange that ahead -- there are plenty of small hotels that are low key and casual.
When you arrive, start out with a tour. It's a great way to launch. After that we had a nice lunch with really fresh seafood at Armstrong's right on the water.
Santa Catalina Island is fascinating. After the volcanoes which formed California and the Channel Islands 60 million years ago came the Native Americans (8,000-10,000 years ago), 
later Portuguese and Spanish explorers, Russian fishermen, and wealthy Americans seeking hide-aways. All this and more we learned in our two-hour Skyline Drive tour by bus, going up and down the lone one-lane road (formerly a horse trail with many hairpin turns) to the airport at 1602 feet up from the sea.
One of the important settlers was chewing gum heir William Wrigley who arrived with his wife Ada in 1919 and bought 99 percent of the island. Today the Wrigley heirs constitute one of the two major landowners -- as the Santa Catalina Island Co. -- and the other is the Catalina Island Conservancy, which owns most of the 48,000 acre island and is dedicated to preserving its interior. On a clear day from the airport, which covers two topped-off hilltops at 1600 feet, they say you can see all the way to Palm Springs 65 miles away. On our way up the hills we saw about 20 American Bison, descendants of 14 bison brought here in 1924 for a Zane Grey movie "The Vanishing American" (Zane Grey lived here and his home is now a hotel). But the bison scattered once they felt solid land, propagated up to about 2000 at one time, and now are back to about 150.
I highly recommend doing some online research before you go. As a tee shirt and shorts destination, you need to make sure it's right for you. Here's a map to start your orientation.
