Check to be sure that your credit card rental coverage or insurance includes pickup trucks. Otherwise you may need to buy the rental company collision wavier to give yourself enough protection. If you bring some large trash bags, those will protect the groceries (except frozen items) long enough to get to your resort. Adjust things so the ruffled top does not face up after affixing the zip tie, so rainwater does not collect and then drip inside. Frozen items, even in a bag, must not be in direct sunlight or in/nearly in contact with a metal surface.