I do the same as Jack.....The Wye to Staten is N.Y.
I use a giant cooler. Built two racks for the bottom that sit 3" up. I fill the 3" space with ice, unscrew the cooler drain plug to allow melting ice water out, put all the crabs on the rack, bellies down of course, cover the crabs with burlap, dump a bag of ice on top of that, then crack open the lid for the ride home. I used to just put ice on top of burlap on top of baskets, but ice seemed to melt before I got half way down 301 from the Wye. Always a plethora of ice left in the cooler when I get home now.