So I did a lot of video watching and blog reading about thrue hike on the appalachian trail and it seems that you only really need to send food and other supplies ahead on two places on the trail and that is Fontana dam and the NOC which I'm planning to do on my 2016 thrue hike . If you know any other places that any of the past thrue hikers had problem finding food and would be a good food drop via mail.