Southern California is not fun to drive around in, so keep that in mind. Also, you didn't say the ages of your kids and that makes a difference but here's some ideas.
The beach. It's about 40 minutes West to the beach (Redondo Beach and Pier is the place to go) but the weather should be good and it's fun to walk along, build sand castles and if it's warm enough (and it often is being So. Cal.) play in the waves. Do stay on the beach and don't go out on the rock jettys to see the waves, every year some tourist gets washed away doing that. Also the Redondo Beach pier is a great place. You can spend a day walking along the beach, and go to the pier. Parking is pretty easy and it's cheap.
Also, near Disneyland is Po' Folks....... a good place to eat if you're missing Southern food, kind of like a Cracker Barrel but much more crowded. Cool model trains run around the top of the dining room.
Also, free and this time of year is good to see, Whale Watching from the Point in Palos Verdes. Nice museum and nature trail. This too is about 40 minutes from Disney but about 15 minutes from Redondo so you might want to combine. By the way, Palos Verdes is where they filmed the opening shot of Falcon Crest (years ago).
Of course, there's Hollywood's Walk of Stars which would take an hour to get to and it is cool to see, but remember if you get your photo taken with the folks dressed up as Batman or Superman that you have to tip them, that's how they survive. Ripley's Believe it or not is there too, and the Egyptian Theater is gorgeous. You'll spend lots of money eating around here and buying things but it is really cool. But don't wander off the main drag.
Check out www.familyfun.com they might have more ideas.