The Grand is cold.
You could store most, if not all of those items at room temperature at home.
Onions, pineapple, melon, bananas, oranges, carrots, apples all have a far longer shelf life than 5 days.
The lettuce, tomato, and cucumbers need to be cool and moist.
They would all be fine in an ammo can. Maybe cushion with towels and keep the softest items on top (melon, pineapple, apples on the bottom).
I would think that keeping it all cool on the way to Lees (cooler that stays in the shuttle rig), and keeping the ammo can cool (damp towel) while on the river would work great.