I assume it's going to Hell and the Turtle Farm. There really aren't a whole lot of attractions on Grand Cayman. Rum Point is a nice beach and of course, 7 mile is beautiful. You can easily do Grand Cayman on your own. The bus to 7 mile was like $6/pp. The shopping area is right were you get off the tender and you can walk to all of the shops without any problem. Grand Cayman is sort of a flat island, like Aruba, not like Jamaica at all. However, if you want to see some of the island, that tour might just be right up your alley. Don't get me wrong, I love Grand Cayman, it's just not a "sight-seeing" island to me. I like to see forests and lush vegetation, hills, and look outs. It's still a very clean island and pretty in its own way.
Hope y'all have a wonderful time!