If they were completely thawed but on ice, yes you can refreeze them. Quite possibly they will be mushy when you thaw them. It can become a mess when you thaw and feed them but it will pose no harm to your snake. If they were still partially frozen and you are currently getting them back to a hardened state by freezing them I doubt they will be mushy. Next time wrap them up with several layers of newspaper and place them in a cooler just big enough to hold them with no ice. They will make the 1 hour trip home and still be hard as a brick.