I will always have my sidearm while out. The only thing that I think is a mistake about taking a firearm in is the location of carry. Holsters on packs are useless, you'll never have it when you need it. I always have my Glock 20 in my chest rig.
I would bet that most shots are already taken inside of 300 yards. The percentage of people that take longer shots I think is pretty low. Plus they are building some incredibly accurate muzzleloaders any more. I know guys being successful at 600 yards.
Man you're making progress fast! I've been kicking around the idea of making a mobile walk-in cool room. Looking forward to seeing the rest of your process.