Can anyone tell me if my GPS will work on the island. I just thought it my help us get around while driving.

Garmin maps since 2010 have the Cayman Islands map set included in their North American map. May help a bit for general area location and points of interest, but I do not really find it that useful. It is a small island and there are not that many roads.

Google "Testudo New Garmin Cayman" for a link to a POI file I created for some Grand Cayman tourist sites.

There is really no need for a GPS on Grand Cayman. It's so easy to get around, just a standard map will do, available at your car rental. Have fun!

I've used them on other islands and have found them useful, if only to mark a few waypoints for remembering where things are later.