Using dry ice

With some planning and prep work you can do this with good results. Freeze as many gallon jugs as you can. Use two coolers. The day before you leave put a frozen gallon in each cooler and close the lids. This gallon will be to precool the coolers. On the day you are ready to leave fill your extra cooler with as many frozen gallons as you can fit. Close the lid and keep it that way until you need more ice for your cooler with food in it. Cooler you are using. Put your food and as many frozen jugs as you can fit in it. The ice will melt quicker in this cooler because of opening and closing to get food and drinks out. When it gets melted pull out those jugs and refill with jugs from the extra cooler.

Block ice is what my dad used on his when the cooling unit failed. I think it would be a great feature to have and "ice box" to enable block ice to be used and have the ice box self drain when empty. This would give the boondockers another option for keeping the fridge cold when not hooked up. Or the folks that are leery about keeping the fridge on while driving.

Paul

Suggest you use a block of regular ice. Will keep things cool for a few days.

I would go with regular ice. If you can get a block of it or freeze your own in gallon jugs it will last longer. There are dangers with dry ice. Linky