I went to lowes and bought cheap square-ish organization containers.
Similiar to this.
I got some that would fit in the cooler we were using.
For longer trips, I will freeze late trip meals vacuum sealed into each one, and separated the blocks in the cooler with cheap cutting boards.
Now I've got ice blocks below with food inside them, and ice blocks above that are purely ice.
And after all that I still like freezing gallon jugs better, they don't make a mess when they melt.