Wow, the rule of thumb over July 4th break will be get there BEFORE the park opens at 9AM. Annual Passes (Except the very highest level) are blacked out next month, so that may help, but I'm betting not much. It's new.
FYI If it rains or storms in the afternoon, that's the best time to go (right when the rain is wrapping up, they will reopen it then)