Plan to be there but don't plan your stops too hard...leave lots of time to let the place show you. You will be amazed at the photo ops that present themselves without much planning, simply because you are there.
The method to my travels these past few years is to simply get there and have an exit strategy anywhere I go. Usually, I find so much eye candy that it is hard to leave, but work and obligations await and they make my travels possible...
When you are out there, also don't confine yourself strictly to the park. There's a lot out there to find, photograph and experience.