Plan in advance… what are you planning to cook? What items do you need for each dish? At what point in the trip will you need the items?
I prepare by making my list. Breakfast, lunch, dinner.
Every night gets a dinner plan… and then I premake as much as possible, then I freeze the portion in a plasic zipper bag laid as flat as possible. So, for example, if I plan to make spaghetti, I make the sauce at home (no, you aren’t going to simmer sauce for hours over a campstove, and why take a glass jar?), let the sauce cool, then pour it into a gallon sized freezer bag. The bag gets shaped to a flat square (press the excess air out) and frozen into that shape. Then I do the same with any other meal that can be premade.
(note- Do as much prep and freeze as possible… it saves time and headache at the campsite. Shape your hamburgers etc.)
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Put the frozen meal blocks on the BOTTOM of the ice chest. You will be pulling them out only as needed, so they won’t get shifted around a bunch. And they will add a cold layer to the bottom.
Next… I put lunch meat in a plastic box (those bags and packets that they come in are fine for home. Transfer your turkey or salami to baggies, then into a box). It’s a one grab search, and nothing will get lost in the bottom.
Eggs in an egg holder.
Milk in a plastic jug (right on the frozen stuff)
Butter, mayo and other condiments that need cooling should be in plastic, and near the lunch meat. I keep my bread in the dry box, but you can decide if you want it cold.
My habit is to keep drinks in a different cooler, just because I want to keep the food from gettng exposed to the outside world as much as possible.
Top the food with a layer of ice packs. Either those blue ice blocks (that only last a day or two), or (my favorite), doubled Zipper bags filled with ice. You can replace the ice when you get the chance, and the bags will form to fit your space.
Now, when it is spaghetti day, pull the froze sauce out, and let it thaw over the course of the day. At dinnertime, it should be ready to heat and serve.
Anything that does not need to be kept cold can be kept in a dry box. This way you don’t use up valuable ice chest space… also, you don’t want people opening the cooler if they are reaching for chips.