On the way to GC, depending on which way you go, you will go by a couple of grocery stores. Probably the easiest way would be to take the Causeway from the airport and go to the Grand Marche in Cole Bay (Dutch side) or stop by the Simply Market in Hope Estates. I don't think there are any grocery stores in GC any more. There was a US Market in Grand Case and I think they closed. There is a bakery almost at the corner of Grand Case Boulevard, very roughly across the street and down a bit from where LeBounty used to be. Truthfully, I think you're going to have some problem with getting groceries there without a car.