I wish I could help you, but I have never heard of them... is it a Southern thing as I do not remember them up here in the cold Northeast.
They must sell them at the candy stores???? I did a little search by googling cherry sours, lots of information there, and you can buy a 5 lb bag for 19.95 online.. seems Target sells them too in boxes, what about buying them before you come and have them with you while you travel.