If you wanted to invest in a super cooler, my son bought one that is supposed to keep things cold for several days!
This cooler was probably $60 (in central Texas), though.... (bought it at a local "big box" retailer that is nation-wide..... (This may be the one that he got.... the ad says it keeps ice cold for 7 days! http://www.walmart.com/ip/Igloo-Quick-and-Cool-150-Quart-... )
(Sorry about the walmart ad, but that was the only way I could see to find what one it was...)
He used it to brine a brisket..... the meat was in a large bag with the brine mix, and it was then put in the cooler filled with ice....
He brined the brisked for 12-24 hours, I believe.... took the brisket out, and left the ice in the cooler.
2 days later, there was still ice floating in the water (from some of the ice that did thaw...)
As long as there is still ice in the cooler, it is keeping things plenty cool.