There is no way you will enjoyably get to do San Francisco and LA done in 3 or even 4 days. Don't even try it. Pick one or the other.
I am from Southern California and live in the San Francisco Area now..
You will/should spend a whole day at Disneyland(from park open to park close). If you dont, you are getting ripped off by the $75 tickets.
Disneyland is around 30+ minutes from LAX (worse if there is traffic). Buying tickets at the park could mean long lines in the morning.
There isnt really much to do/see in Hollywood. There is the walk of fame and stuff but that gets old pretty fast. You may get to see the security gates of Hollywood studios(which are mainly in surrounding cities) but that is about it. I guess you can go to Universal Studios (the theme park/movie studio), but there again is a daylong trip to get your money's worth.
Helpful hints for non-Californians:
Southern California:
Nothing is close to anything else worth seeing (e.g. everything is spread way out)
You have never ever seen traffic like in LA, it is congested at all hours and a parking lot during rush hour
Orange County has some of the widest freeways that I have seen in the world where the 405 freeway is I think 10-12 or so lanes in some points (and these congest into 6-8 lanes when you enter LA county)
You must drive everywhere worth going
Parking is horrible in Los Angeles, especially in touristy places. Expect to pay and circle for spots.
Public transportation is worthless, dont bother trying to use it in Southern California. Everyone there uses cars so you should too
LAX is a nightmare to get to in traffic. It is also busy almost all hours of the day and night
If you want a smaller, less congested airport closer to Disneyland, try Orange County/Santa Ana/John Wayne (Airport code: SNA)
It is extremely easy to get lost in Los Angeles -- Try to stay on major streets and BUY A MAP/use a GPS
The LA metro area is this gigantic suburbia that I have never seen anywhere else in the world. I have flown all around the United States and you know you arrive in Southern California when you see lights in all directions that extend as far as you can see at altitude
Weather is better as there usually are only two seasons, warm and hot in the year.
Bay Area:
If you want to see nature and natural beauty, come here (redwoods, coastlines, bridges over the bay, cleaner air)
You can still see big city life in San Francisco
The rest of the bay area is suburban, but it is not nearly as large as Southern California
Public transportation in San Francisco is pretty good for reaching most touristy places (parking is horrible in SF) - Use BART and/or MUNI and ditch your car at an outlying station
Great concentrations of museums in San Francisco
Weather is colder at this time of year