Very important -- DO NOT EVER touch dry ice! Always use gloves when handling it, and even then, better to keep it in a paper bag or something.
I frequently use dry ice when taking frozen food to my cottage in Maine. 10 lbs. of dry ice, in a nice cooler, will keep things frozen pretty well for 2 days, especially if it's packed pretty tightly. I usually find that the dry ice is mostly sublimated when I get there, but the food is still frozen.
I wouldn't use dry ice for a camping trip -- too many potential problems. John's advice above is right on.