Long arm - AR-15/M4gery 30 rnd magazines, semi-auto is plenty, select fire is worthless as you are just spraying and praying. While Garands, M14s, M82 are awesome, in this specific situation are too long and cumbersome to move quickly from one target to the next.
Side arm - High capacity, .22, .32, 9mm, .40, .45 doesn't much matter. "Stopping power" is irrelevant, even a hot loaded .45 with a heavy bullet is not going to bring a person to a dead stop, much less a zombie.
Support - most anything in this category is both heavy and cumbersome and in a four mile hike (with immediate evac) is nearly worthless. You are going to be wanting to shoot & move, not hunker down.
Armor - mobility is key, anything that would weigh you down will tire you out. For a 4 mile distance speed and stealth are the biggest advantages. Pass on the armor.
Other weaponry - A couple of decent knives and perhaps a crowbar/hammer (for breaking through locked doors/windows)