We are in Northern CA, and my kids have that whole week off of school and then back to school on the 26th. My guess it will be busy. We've been in November before, but it was earlier in the month and it was one of our best trips (very low crowds).
I've learned my lesson the hard way and we won't go around any holidays/holiday weekends or spring break any more. We will be there in July, but plan on doing a lot of swimming at our hotel during the day and the parks in the early morning and at night.