I thought from your initial post you weren't hunting. Thus the hunting regs don't apply. You're just out riding around on your ATV. If that's the case, in my opinion, the only rule that applies is the carry of the gun in/on a vehicle. Even then, it's covered under the wildlife statutes (Title 33), not the criminal statutes (Title 18).
I'd say f you have an empty chamber on your cased AR you'll be fine. That's what I'd do.