I just got back a week ago, we stayed from opening (8am) till 11pm (i wanted to stay one more hour to make it the whole day, but family was tired

)
anyways, we did about 15 rides going back and forth from
Disneyland & California Adventure. We also were able to watch the fireworks, have lunch at blue bayou, stop in the shops from time to time, get hats made, take pics with characters, & stop for snacks.
It's amazing how many rides you can get on when you arrive right when the park opens! We rode a majority of the bigger rides (indian jones, thunder mountain, matterhorn...) before 11am, with haunted mansion, pirates, jungle cruise, captain e o, thrown in between with a fast pass for space mountain at noon!
it worked out well!
this was on a friday, and crowds really got significantly larger around 1 or 2, and on Saturday the crowds really gathered around noon.
its best to get the rides that draw longer lines early in the morning, and if you need to, grab a fast pass and ride smaller rides until your fast pass time frame arrives.
we got tower of terror fast passes, watched the aladdin show, then came out and it was time for us to get on tower of terror! perfect timing!
have fun!!