Jason,
Turning on your GPS will kill your phone in less hours than it takes to hike this trail. Your phone, if not in airplane mode, will be constantly trying to find a network that does not exist. My phone last about 8 hours in the locals when I forget to put it airplane mode...and I have the GPS turned off.
The best course of action is to have those in your group buy the pertinent maps and study them. When I first did this hike I was hiking about 3 months. I studied the maps before going and the only surprise I had was how stinking hard the upper part of this trail is on your body. I knew where all the stream crossing were, when the trail was easy and hard; and junctions for Lone Pine Lake and north bound JMT.
The only thing you might need your phone for is to say, "I'm on the top of the world, Mom" and for assistance when thing go terrible wrong. You will be hiking with 160 of your new nearest and dearest friends...especially in the morning.
Last edited by wbtravis; 05/05/14 08:55 AM.
