Reddit mentions of Disneyland's Hidden Mickeys: A Field Guide to Disneyland Resort's Best Kept Secrets

With a 5-day park hopper you will definitely see everything, so no worries there :)

If you really want to ride Radiator Spring Racers don't go in the FastPass line. I watched it grow almost to the length of a regular queue line. Instead go right to RSR, ride it, and then hit the FastPass a little later when the return time is in the evening: riding RSR at night is really cool as well. In fact, make sure you hang out in Cars Land and the parks at night and don't retire early, they take on a different feel at night and the atmosphere is great.

Grab a copy of The Imagineering Field Guide to Disneyland, it has a lot of interesting information you can read up on as you travel there. Picking up a Hidden Mickey book can help you scour every square inch of the park too.

And don't be afraid to swallow your pride and visit some attractions that might seem dumb :)

Go on a hidden Mickey hunt!

They sell this book around the parks. It's the one we bought to help us find them.

There is a hidden Mickey handbook that you can get at a local bookstore. It is great fun to see how many one can find in the park. It is small enough that you can carry the book with you in the park.