For general cooler packing, here are a few tips. Pack raw meats, fish, and produce sealed in plastic bags on the bottom. Next layer in produce, dairy, eggs, and perishable condiments. Save space by packing just what you think you’ll need for the weekend. And remember to fill the cooler all the way up; the ice will melt faster if it’s full of room-temperature air.
If you store your cooler in a hot garage, bring it inside the night before so you can start with a cooled-off vessel. Use solid ice or reusable gel-filled ice packs on the bottom, pack food, then fill in the gaps with bags of cubed ice. Once it’s packed and ready, stow in the trunk, away from light, and put a blanket or sleeping bag around it for extra insulation.