I've been going to Burning Man for a few years - I have type one and use two kinds (three one year) of insulin out there - and I kept my insulin cold with freezable gel packs. Use one in your carry case, switch it out with one being kept in a cooler, repeat.

This works because ice is readily available at Burning Man and you have a camp that's near by.

I've also gone on multiple day hikes and used a similiar system, or just kept it in an insulated pack without any kind of freezer/cooler. Insulin doesn't have to be kept super cold or in the refrigerator at all times, it just can't be in really hot temperatures, so if you're hiking in a temperate climate, it shouldn't be a problem.