During our resent trip to the Allagash in ME we came up with a great idea to keep our food frozen.

Layer it in Saw Dust.

We started with a layer of SD then the 4th days Foods, another layer of SD to fill all the voids and air spaces, then a layer of refreezable blocks, more SD, 3rd days food...

Day 4, not thinking, supper was delayed because we had to thaw out the meat.

With care, I think this method could be used for at least 2 and maybe 3 more days if you use a second cooler for the later meals in the trip that isn't openned in the first part of the trip.

SD burned after cooler was empty.