Here is a personal packing list that Quiet Thunder has developed over the years.
You may not need to bring all of this, but here it is...
Quiet Thunder has been experimenting with this for the last few years.
FIRST: NEVER TOUCH DRY ICE.
Dry ice comes in cubes and blocks.
The blocks last much longer.
You can order blocks of dry ice from Glacier Ice, 130 High Street, 805-543-0785 in San Luis Obispo.
If you put 2 or 3, 5 pound blocks of dry ice in an open bag, it will keep a large block of ice in your cooler cold for about 3 days. You can then use this block of ice to replace your initial block that you have in your cooler with the food.
Another method is to put a 5# bag of cubes or a block on the bottom of the cooler with the ice block on top of it, then your food above that.
Anything that is next to the dry ice will freeze. You can keep sealed foods in that cooler, just not right next to the dry ice.
Dry ice sublimates rather than melts, which means it gives off CO2, so it needs to breathe, can't be sealed up.
LAST: NEVER TOUCH DRY ICE.