I agree that 10 days is a long time to stay in Anaheim. You may want to break it up a bit. San Diego is a great option for spending 2-3 days. You can go to Sea World, the SD Zoo, Wild Animal Park, USS Midway, and the beach. There are also some local wineries, if you like to go wine tasting.
In LA, you might want to do Universal Studios. Depending what time of year you're visiting, you could catch a sporting event. If you enjoy water parks, there are a few choices.
Lastly, if you really want to take a drive, Las Vegas is only about 4 hours from DL by car. Certainly a lot to do there, and you could easily go for 2-3 days.