Hi again Lisa! St. Thomas and St. John are such beautiful spots, I'm so glad you'll get to experience the
St. John Island Tour Port Adventure! I can't think of a better way to experience a bit of everything there is to offer on that island!
You can expect about 15 minutes of shopping in Cruz Bay at the end of your tour, but depending on how quickly the previous parts of the tour run, that could be extended. Even 15 minutes of shopping in that area will allow you to experience the local flavor and pick up a souvenir or two. Each tour is different, which is what makes the Port Adventures so exciting!
Keep in mind that your tour boat will bring you back to the port area in St. Thomas with plenty of time to explore there before you need to re-board the Fantasy, so I promise you won't lack for shopping time on those islands.
With only a few more weeks until you set sail, please let me know if you have more questions! I bet you are really excited as your cruise inches closer and closer, Lisa!