small observation on refrigeration at Burning Man -
There's a big difference between foods that have to be kept cold (dairy, meat), and foods that are just better eaten cold (fruits & veggies, beer/soda).
For the former,you need a biiig cooler and lots and lots of ice because it's gotta stay cold 24x7 for the whole week.
For the latter you really only need a small cooler that can hold as much as you plan to eat/drink each afternoon and one bag of ice per day. Throw what you want to eat/drink for the day in the small cooler, add ice, and let chill for an hour or two.