I know it sounds simple enough, grab a cooler and throw a bunch of crap in it, add ice, done. The fact is, there is a little bit of a science to properly packing a cooler to optimize your festival from start to finish.
The first trick of the trade is to gather up everything you may want to include in the cooler goodies. If you have beer, sodas, waters, Gatorade, and food, for example, take a few of each of the drinks and pack those. This way you can have a little of everything cold and ready to drink. Don’t fill your cooler with beer and leave the rest in the floorboard of the car. Put the beers on the bottom and the non-alcohol drinks towards the top. If you pack the cooler in the back seat of the car you can reach in a grab cold drinks during the road trip so you want the non-alcoholic drinks to be the easiest to grab. This method also keeps the beer ice cold at the bottom of the cooler so you can pop a cold one when you safely arrive at your festival.
If you have the freezer space, you can freeze a bunch of water bottles and put those in the cooler in place of ice to keep your items cold for the drive. This saves you money on ice for the beginning of the trip and also allows you to have super cold water. Water frozen in bottles will not melt as fast as ice, buying you some time with materials you already have.
Dry ice can also be an asset to you. You can usually find this in any grocery store. It also keeps longer than regular ice, however you have to remember not to handle it with your bare hands or consume it because it can be dangerous. However you choose to fill the cooler, it is a good idea to chill it down before you start down the road. Food can easily spoil if it sits in the back or trunk of a hot car even for a few hours.
As far as food goes, there are some items that have no problem rolling around in a cooler but for most, you need to keep them separated from the general population. It has taken me too many failed experiments to remember to put food either in a separate cooler or a special container. Here’s an example of why: Let’s say you buy a bunch of cheese to make delicious camp-side grilled cheeses. You open the cheese, use a few slices, and throw the cheese back in the cooler. The next day it is likely your cheese is nothing but a soggy pile of cheese looking crap. There may be one or two usable slices and the rest is yucky. All you have to do to prevent this problem is to pack your food in Tupperware containers or really well-sealed bags. If you have space you can put it in a separate cooler all together and just use dry ice or multiple freezer packs to keep it cold.
During the weekend you will definitely have to fill up on more ice. Just remember when you get new ice bags to leave a little in the bag rather than pouring it all in the cooler. This allows you to use the still bagged ice to make mixed drinks or whatever sort of cold drinks you want without having to use the dirty ice that everyone is sticking their nasty hands into.
Keep the cooler in a shady spot so that it doesn’t melt as quickly. If you leave it in the car it will likely get super hot so pull it out and store it someplace cool if possible. If you do pack the cooler in your seats make sure and put a towel or tarp under it so you don’t get that awesome mildew smell by the end of your trip.
Once the ice melts and it’s all water, do not just dispose of this. Cold water can be an asset to you. Keep a little in the cooler to mix with the new ice and keep everything constantly cold. If you drain the water out you can put it into containers and use if to wash dishes, clean off your feet, or anything else you may need extra non-drinking water for. Having a little cold water in the bottom of the cooler can also be helpful for cooling you off at hot summer festivals. I like to dip bandannas or small towels into the water and throw them on the back of my neck or on my head to bring my temperature down a few notches.