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.