We'll be doing this exact (well, sorta) itinerary beginning this Friday. We're doing the CityPass as suggested by Kuusimo (beat me to it!). We'll be driving in from Phoenix, jumping right in with both feet as we visit SeaWorld "on the way" to our resort (timeshare exchange; in Capistrano Beach on the southern tip of LA, nicely central-ish to everything we're visiting).
Fri: SeaWorld
Sat: DL/CA -- mellow day, just seeing the characters, shows, parades, fireworks, etc
Sun: Universal -- hopefully weekend traffic into LA won't be nearly as bad
Mon: DL -- rides, rides, and more rides, with help from RideMax
Tue: free day....beach for shells? Hollywood Walk of Fame? laundry? nothing? lol
Wed: CA -- rides again, with help from RideMax
Thu: Wild Animal Park
Fri: on the road again, headin' home
The wife and I visited SDZoo a couple years ago, so I for one am not too keen on visiting there again so soon (not meaning that in a negative sense, rather I'll wait a few years for the next generation of animals lol). The kids have been to zoos recently, so I think the WAP will be "different enough" to make the grade. It may not be "extraordinary" as alluded to in an earlier post, but I think it'll be "good enough".
I would say DL/CA/US have the most to offer, so visit them on the weekend to make use of the longer hours. Hours for SW/Zoo/WAP are pretty much the same no matter what day, so a weekday it is. SW (5pm), Zoo (4pm), and WAP (4pm) all close early, so that might leave evenings free for additional LaJolla/SD sightseeing.
If you can still find them, the 2005 CityPass has Knott's Berry Farm instead of Universal, good until the end of March.
Can all this be done in a week? Certainly, but then again, we're psycho tourists.
We did all four WDW parks, Blizzard Beach, and a day at the beach in six days a couple of years ago. While our visit to AK was cut short by rain (we can put up with some rain, but it just kept pouring and then it started getting chilly, so that was enough), I feel we got great value out of each visit. We saw most of the characters, rode most of the rides. I don't think we rushed a great deal, the kids stopping for characters helped slow things down (I *tried* to rush, but the best laid plans, as they say lol).
As was said, you know what you're in for, so plan accordingly. Break out a calendar, visit the park websites for their hours, and start plugging things in. Alternate a short day (WAP) with a long day (DL), for example. 3-4 long days in a row could exhaust you. Put a free day in the middle, for doing light stuff (LaJolla) or nothing at all.
Good luck and have fun!
Bill