I made a trip to Acklins last April (going again in '08), and acquired a pair of Orvis Flats Hikers. They have a removable thin neoprene sock with built in gravel guard, and a sturdy lace boot. I wore a moderately thick pair of synthetic (probably polyester) socks inside. I also had some neoprene gravel guards that went over that. The arrangement worked well, and we had some sections with thick marl to wade through. I did not have any blister or abrasion problems. I got the boots via ebay at a good price.
Another possible suggestion is to wear the boots on the airplane flights, so you don't arrive without them.