Cooking for large groups over a wood fired grill, I sometimes used a camping cooler to finish off things like baked potatoes, stews, soups, casseroles, etc. buy wrapping with a blanket and placing the item in a camping cooler. This worked great to finish the cooking and also to keep items hot as another course was cooked on the grill or stove. This is the same principle as the haybox and I already had the large cooler. I like multiple functions. I guess I was a permie before it was cool!
