If you turn off cellular data and Wifi, do you really need to mess with changing your e-mail fetch and cloud settings? I'd assume that if all of your communications are off, it's not going to waste any power trying to pull your e-mail down.

I'm interested in where this thread goes. I did a 40 miler last weekend and my phone was down to 30% at the end. I'm doing a 60+ miler in a couple weeks and am seriously worried about running out of juice.