That is something that is fairly easy to research online. You can visit all of those sites and get prices on admission, book your hotel stays and car rental if you will have one and then add it all together. The part where it gets hard to estimate is food because food tends to expensive(paid around $15.00 a day for a breakfast buffet per person). If you want to keep to a tighter budget you just need to give yourself an approx amount that you want to spend on food each day. Planning a trip myself going San Fran to San Diego stopping in Monterey, Santa Barbara and Santa Monica along the way and just hotels and airfare is costing us about $3,000 for 2 weeks. We are staying in mostly marriotts and a couple of nice to really nice bed and breakfasts.

You're going to have to do some thinking on this one, your budget being most important. You'll have the cost of each attraction (which is often fixed and high), transportation, hotels and food. I'd suggest you get a guide book to California. We used "Where to Take the Kids in California." It was great. Also, Fodors, Frommers and others have good ideas.
Hotel and food costs are the easiest to reduce. You can find good hotels most everywhere for under $200/night. Some may be much less.
If you have specific questions re choices in certain cities, with the number of people in your family, ages of kids, budget, you might find more help on this web site.