I agree with ddbutts, we were there 24th - 29th and it was hot, crowded, and long lines. I've come to the conclusion that the early entry feature is a bust - especially at AK. Between the lines at the bus stop (AKL) at 7:30, the bag search line at the park (AKL and MGM especially), and the fact that it is a magnet for all of the resort guests, it just isn't worth it. In fact, next time I am going to look at the early entry as a way to plan which park to avoid.
Good luck, I hope the heat and the lines subside a bit. Also, the brief afternoon thunderstorms extended well into the evenings last week.
On the bright side, you will love AKL. We were fortunate to get an upgrade to a Savannah room even without asking. The numbers are on your side (for the upgrade) if you book a standard room. There are only a hundred and some standard rooms and seven hundred and some Savannah rooms. We saw animals constantly outside our 5th floor balcony. My Son ran to the balcony each morning when he woke up and every time we returned to the room.
I didn't see the need for the bug spray that others have mentioned, but a pair of binoculars are handy.
The Boma buffet is the best meal I have ever had in my life although a bit pricey. The wide variety of flavors and the quality of the food is incredible.
Mara is not that great, but a good fill in if you are caught in a pinch.
Have a great time!
