For Gorge Waterfalls 50K on Sunday, I've started my packing, and repacking, and checking, and repacking. ;-)
I laid out exactly what I wanted to carry with me for 9 1/2 hours. Below is the anatomy of my UltraSpire Surge pack. Note I will also put my phone (I always feel better having it on me, just in case) in the waterproof pocket the camera is in, and may chop up half a bagel to put in the main pack compartment for added fuel since aid stations are 10 miles apart. Click on it to see the picture big with text!
Now to lay out my apparel and gear and inventory!