how far, what required equipment, ammo etc
if you are not used to it, go as light as you can
fro 3 days you can go without food, gotta have water, maybe a filter or chemical purifier
i wouldn't take extra boots, maybe socks, but going 3 days without taking off boots is not unreasonable, if you feet are used to it (sounds like yours are not)
extra socks are very much welcome if you are wet and cold. "baby wipes" are nice, and light, again for 3 days you can be funky without harm
heat tabs, and candles that you can light under a poncho to warm you up, stove is probably extraneous (i did have a team sgt who would take a small iron skillet and bacon if less than 25 miles or so)
it is all practice being miserable anyway, don't kill yourself aiming at creature comfort