We've stayed at the GC twice now and it was great, but it's more points. The GC is great for it's views and also direct private entrance into CA. The DLH is very nice outside (we've never seen the rooms) and it would be a pleasant walk throught DD to get to the parks. Have you considered Paradise Pier? It's still fairly new and has fewer points, although it's off to the side a little bit.
I second Jim's other theme parks. KBF is pretty neat. US is very different from USF, but also similar in many respects, but worth the trip.
SW in San Diego is different enough from SW in Orlando and worth a stop. And of course the zoo in San Diego is great. (Although lots of hills).
You might also consider going to Hollywood and taking in an NBC TV taping. They're free, many of them on Thursday nights. They often hand out tickets at Grauman's Chinese Theater (The real one, not the reproduction one at WDW's MGM Studios

), or you can go right to the NBC Studios (they're nearby to Grauman's) and check. CBS and ABC Studios aren't as handy to get to as NBC)
Keep in mind driving in California will be very different. First, the place is huge. You basically have over a 100 miles of urban development all the way up and down the coast. It's very crowded, and try to avoid rush hours at all costs. Look at your maps carefully before setting out. It's easy to get caught in the wrong lane and unable to get to your exit, so think way ahead while driving.
If you go to San Diego, you might want to head down into Mexico for a few hours. It's not that much further. If you do, don't drive across the border. Instead park at the border crossing (it's pay, but only a few dollars), and walk across the border. That'll put you right into all the areas of Tiajuana that are interesting. When done, just walk back across the border (you'll have to walk back a different way, crossing over a pedestrian bridge and going through U.S. Customs. Be sure to carry ID with you, such as a driver's license just in case they need to check.)
While not practical for this trip, if you were staying longer, there's a Ton of stuff you could do. Go see the Queen Mary, (The Spruce Goose is no longer there), take a side trip to Catalina Island, or even take the PCH for a drive up north toward San Francisco, stopping at Pebble Beach and taking the 17-mile drive there. California has some of the most beautiful scenery you'll ever see.