I'm going to run a Kifaru Scout with my pistol and spare mags on the belt. Rifle slung. Insulation and water bottles in the pack, as wella s my eye and ear pro. Might wear the eye pro, not sure.
I don't want to give medical advice, but it is only a 6 mile run, and not all at once. I don't mean to downplay it, but the temps won't be like they were when you guys did it last. I am not a believer in constant hydration during an event. I know that goes counter to conventional wisdom, but the human body is meant to be able to go for a while without needing water. I've run 10k's in really hot weather, and never drank till it was over. I tend to stay well hydrated, and know what my body needs. It always cracks me up at crossfit when people constantly stop during a 1 hour workout (only 20 mins straight, usually!) and drink. They are not the ones in top shape, ime.
I intend to drink at the shooting points, which I believe will be more than frequent enough. Can't be more than 3 or so miles at a time, I assume. Maybe I'm wrong. Any idea how long the longest leg of the run is?