I heading to Six Flags Magic Mountain. I've never been there, so if anyone has any suggestions or comments they will be appriciated. 
We are also going to cruise the california coast on the way back to WA. Thanks. 
ROLLERCOASTERS! 
Hope you have a fun and safe trip!
Six Flags Magic Mountain was very fun! The rollercoasters were crazy. It so huge you MUST have the map to get around. Bring your sun block and your walking shoes.
I would definitely recommend it to anyone who likes extreme rides. Yes, they have some mellow rides as well, as my wife forced me to discover, and yes, they were fun as well. (Don’t tell my kids)
It was 108 degrees outside and the lines were very long for some rides. They try to alleviate the pain of waiting in line by misting water on the waiting patrons, but I didn't find that to be much comfort, it just made wet as well as hot. We actually skipped one rollercoaster because the wait was 3.5 hours, and we were hungry.
Speaking of hungry, we went to the McDonalds at six flags and spent $9.95 on a double quarter-pounder meal! While that was expensive, the souvenirs were quite reasonable. We bought two hats and a pair of sunglasses when we arrived to keep the sun off our faces ($24 total). We also bought two very nice sweatshirts for $24 each.
We got in for half price ($22 per person) because we brought coke products to the ticket counter. For just under $100 you can get a "fast lane" pass that allows you to go right to the front of any ride's line. Something that we might actually consider if we go back, since we only had time to hit 6 rides in a whole day.
Overall we really enjoyed it, and would return, but probably during a less busy and less hot time of year.
I lived only about 2 miles from 6 flags for 7 years and I found that if you got there before the gate opened and headed for the most popular rides first, you always got to ride more than once and this is on a Saturday. When you are tired of the wild rides and it gets to be very hot, that's when you head for the rides that are inside. If you are the hardy one, stay until midnight and they always have a lazer show. When its 1 am then it's time to go home. I went every year while I lived there in Texas (if that's the one you are talking about) Great place to have fun. I made my kids ride everything. I figured the whole day and more was enough to take care of their need for speed until there next year to go. In between the rides there was the BMX show, bird show and lots and lots of activities. I'm glad you had a good time and you will want to go again someday. 
We actually went to the Six Flags in California, but I think you have a great idea for any of them.
We could of arrived a little earlier, but my kids had to hit the pool before we left the motel. But we did stay until closing.
We must of walked for miles; that place is HUGE! 