Well, let's look at the cost and some other info...

A one day, one park ticket to Disneyland is $66 for adults (10 and over) and $56 for kids 3 thru 9.

Disneyland is the first and the classic Disney park. It opens earlier than DCA and stays open later (on most days).

And while some of the attractions are also found in Orlando, there is enough unique or different enough attractions to full a complete day. For example, Fantasmic! is much better here in Anaheim, larger and even a different script (Anaheim features a Peter Pan scene on the Sailing Ship Columbia, while WDW has a Pocahontas scene instead). The one drawback in Anaheim, no seating, you just find a piece of the sidewalk along the edge of the Rivers of America and place your backside on the concrete.

Disney does sell a One Day ParkHopper for $25 than a one day, one park ticket, but all you are doing is giving up some of your time at Disneyland for DCA.

And DCA has not had the best reviews, in fact, Disney is planning to spend over $1 Billion in a major makeover (more than the total cost of the original park when it opened in 2001) to try and turn it into a place that folks think it is worth a one day ticket.

Also, DCA has a lot of WDW copies, including Tower of Terror, MuppetVision, Playhouse Disney, It's Tough to be a Bug, Soarin' and Toy Story Mania!.

If you wanted to do a second day, a 2 day ParkHopper is the same price as a one day, one park ticket, so that is an extra $66 for adults (including the 11 year old), and $56 for the two youngest. That is over $300, and, IMHO, just not worth it.

Since you don't live near the ocean, a day at the beach sounds great. I have driven the "scenic" route many times, you can head south down Harbor to Newport Beach and Balboa Pier in the morning (I like catching the Balboa Car Ferry for just a couple of bucks for a quick boat ride and then when you exit Balboa Island, take the Coast Highway South, plenty of views and places to stop, including Laguna Beach. When you get to San Clemente, you need to get onto Interstate 5 until you get to Oceanside, when you can once again get onto the Coast Highway (the old main highway between LA and San Diego) and take it to the La Jolla area, where you can get back on the freeway.

I think that is a nice leisurely day, and you can spend the money saved on a nice meal somewhere along the way...

Here is a marked Satellite Map that shows the basic route, it was "quick and dirty" so the route might be slightly off the road when you zoom up close (use the bar on the left side of the map), but it gives you the idea, lots of coastline and scenic views.

If you want some nice historic hikes and views, the Torrey Pines State Park, just south of the State Beach, is a nice place to spend a few hours. It is at the end of the route, so you might end up in the area too late.

http://www.gmap-pedometer.com/?r=2049757

If you are out of town and never been to California Adventure, then yes, it is worth the visit. It has the old Electrical Light Parade for one. It also has the Tower of Terror, Soarin' over California, Screamin', Grizzly River Rapids, Monster, Inc., and Mulholland Madness. These are worth the visit itself. And for characters, they have the Incredibles and Monster, Inc over at California Adventure. And the princess dining at Ariel's Grotto. The animation building and the Aladdin play are a must also.

Our family enjoys California Adventure and we recommend it to your family!