You picked a great time to visit the West Coast. I'm a local but have done pretty much of the same things with my Aussie fiancee - NY, Grand Canyon, Vegas & drive from LA to SF last year. Just wanted to pass along a few recommendations...

1. See if you can swing a voice-prompting GPS from the car rental company. It will make the drive *so* much easier. There are also rental companies or you can even buy a low-end one for under $200 USD.

2. Get a cheapie pre-paid cell phone and calling card. I'm paying about 2.3 cents per minute to call Oz.

When we travel on a road-trip, we generally don't worry very much about the hotel reservations. It's nice to be able to extend a day or take a detour off your itinerary. In mid to late afternoon we'll ask the GPS for a list of nearby hotels & call around. If a hotel is booked they're usually pretty good about recommending someone else. If you still have problems one nice thing is that late afternoon here is mid-morning in Oz & you can call a friend to do a Google maps search for you.

I'm sure you're getting great advice in the other forums, but wanted to just touch on a couple of West Coast things.

LA area - Obvious choices:

Attractions: Disneyland, Knott's Berry Farm, Magic Mountain, Universal Studios
Off Beat: Venice Beach, Hollywood, Rodeo Drive, Farmer's Market, Tickets for taping the Tonight Show, game shows, Dr. Phil, Ellen, etc.
Culture: Getty art museum, Hollywood Bowl

San Diego is only 1 1/2 hours south of LA - World class zoo, Sea World, perhaps a trip to Tijuana Mexico? (If so, make sure the rental agreement allows that & get a daily Mexican car insurance policy BEFORE crossing the border.)

Enroute to SF - I'd take the 101 freeway to Santa Barbara & spend 1/2 day or so. Pretty coastal town. Cut over to Pacific Coast Highway and drive to Big Sur, gorgeous coastal views and magic if you catch the sunset. Up to Monterey, don't miss the Aquarium - arguably one of the world's best.

In SF - I'd avoid driving in CBD, parking is horrendous & very expensive. We paid $30 to park for a few hours in Fisherman's Wharf. Public transportation is convenient and cheap for anything you want to do in the city. Do drive to Twin Peaks to get a spectacular view of the city, bridges and bay.

Have a great time & sorry to ramble.