With regard to the coleman ice box, I have a 30" long blue one. Out of curiosity I did an experiement last summer when it was in the high 20's outside during the day.
I filled the box half full of ice cube, covered the ice with a dry table cloth. Shut lid and left box in garage for 3 days. On the fourth day, I opened the box, drained the water and found with 1/3 of the original ice left. I guess it ain't too bad.
However, if you have to keep opening and shutting the lid a dozen times during the day, I don't believe the ice will last more than 2 days (depending on the outside temp of cos).