Pre-chill everything.

Yes. Pre-chill the cooler, the drinks, the food, and the ice packs themselves.

A warm cooler melts ice fast. Room-temp drinks turn into lukewarm soup by noon. So the night before, stash everything in the fridge. Throw the cooler inside too (empty, obviously). If you can’t fit it, at least fill it with ice water for 15 minutes and dump it before packing.

Packing order matters: heavy drinks on the bottom, lighter perishables on top. Use a layer of ice packs or block ice between them — blocks last longer than cubes. Fill every gap with ice or frozen water bottles. Air is the enemy, so stuff towels or empty space with ice.

One more thing: separate cooler for drinks if you’re going to open it constantly. Food stays cold when you’re not fishing for another beer every hour. Future you (and the potato salad) will thank you.