When I went last year I got a Polar Bear cooler, froze the meats, pre chilled the cooler, and put in the cheeses on top of the frozen meats. They were still frozen when we got to St Thomas 7 hours later. Turns out most of the beef and cheeses were available at Riteway, but they wouldn't have been as nice as I can get in the states. I vacumsealed a whole tenderloin that I cut up into steaks so that was very nice to have on the trip.
Just some advice, when you get off the ferry, make sure they put your cooler on shore. When we got off they tried to hide it on the ferry while we were in line. I was observant and went back onto the ferry where I found it pushed to the side and noticed that someone had opened it. I got it and carried it off.