My normal camp cooler is a 48 qt. poly Igloo, about 18 years old. If I pack it with two half-gallon jars of block ice and make sure at least half of the food that goes in is frozen, it will stay cold (under 40 degrees) for 3-4 days when temps are under 60 degrees, and 2 days if temps are 70 or above.
I use two half-gallon Rubbermaid jugs filled with still water, hard freeze them to 'blocks' in my home freezer, and then either refreeze them or buy another block of ice and drink the jugs of water on the road.
The 48qt is a little big for my galley, though, so I have to carry it in the pickup. I have a 32 qt steel belted Coleman from the 60s that fits much better in the galley, but doesn't hold ice nearly as long. Too bad, 'cause it's a neat older cooler.
I also have a 24qt Igloo poly cooler, about 20 years old, that is tall and narrow. It will stay cold (under 40 degrees) for 3 days if properly iced...but is just the teensiest bit too small for a whole weekend unless it's winter and outside temps mean I don't need too much ice.
Gaelen
cooler junkie