A few things.
1) you are worrying too much that when you turn the phone on, your emails, etc will drain your phone so much before you get to the parks. If you phone, fully charged overnight, drains that quickly, then something is wrong with it. As someone mentioned, just disable your push notifications for emails. Set the frequency of emails for either manual, or the longest interval. Then turn off notifications for your game apps (WwF, etc). I have an Android but I make sure in my Running App screen, I shut it down and turn off the notifcations. Also, turn off Wifi, and when you are in an interior ride (soarin, SpaceMountain, etc) with terrible signal coverage, put that phone on Airplane mode until you get out. When your phone cannot get a signal, the cellular radio still hunts for a signal and uses up battery trying to find a signal. Go on a flight with no cell coverage and leave the phone on and tell me what your battery life will be when you arrive. Barely usable I tell you.
2) Scrap the AA charging things. Yeah, you can always pop a AA battery in, but do you want to carry a pack of batteries AND the charger? I doubt it. Get a small charger, at least 1.5-twice what your battery holds. I use this one
http://www.amazon.com/PowerGen-Exte..._1_3?s=wireless&ie=UTF8&qid=1337825817&sr=1-3
I can get down to 30% and charge it back up and still be at 50% capacity on the charger. Plus its cheap at $22. The only downside for you is that you'd need to bring your iPhone USB cable and connect it to the USB port on top. IT has an attached MicroUSB cable on the side, but can charge non-MicroUSB items by using the standard USB port. ITs also a flashlight too. ITs the size roughly of an iPod Touch. Get something like that. There are other ones with more mAh capacity but most are either too bulky or too much $$$.
