Dry ice in a cooler works great. Vent it and don't touch it.

Yes, dry ice keeps things cold way longer than regular ice, but you need to be smart about it.

Dry ice is -109°F – it doesn’t melt, it sublimates into CO2 gas. That means your cooler will stay well below freezing for days, but a sealed, airtight cooler becomes a CO2 bomb. The gas can build up pressure and, more importantly, displace oxygen. If you open it in a confined space (like a car), you could pass out. So always leave the cooler slightly vented – crack the lid or use a cooler with a drain plug that you leave open.

Never touch dry ice with bare skin. It causes frostbite almost instantly. Use heavy gloves or tongs. And don’t swallow it. Also, don’t store it in a glass container – the thermal shock can shatter the glass.

For food, dry ice works best as a companion to regular ice: put dry ice on the bottom, then a layer of newspaper or cardboard, then your food, then regular ice on top. That keeps frozen stuff rock solid without flash-freezing everything.

Bottom line: dry ice is a beast for long trips. Just vent the cooler and wear gloves.