We made a trip from the south to ND for a bowhunt, 3 days travel for me. My buddy packed lots of food, because we were staying in a rather remote area. He put a small chunk of dry ice under regular ice in one very large cooler. After several days we finally had to use brute force to break the ice to get at the food. Broke the plastic containers too in the process, but we could eat!
In the late '80's we flew to CO for a hunt. I had a 4 pt. longbow elk processed out there and shipped to MS, and the shipper used dry ice. It was frozen hard after more than 24 hours transit time.
My wife got a 5 pt. the next year, but we had driven out, over 30 hours. It was cold and the elk mostly froze while hanging. We halved the elk and wrapped it in a tarp and our sleeping bags for insulation, and the meat was still mostly frozen when we processed it three days later.
Conclusion: dry ice is overkill.