I posted this on Facebook as a suggestion to someone who only had one day.  This was right after we left when everything was fresh in my mind.  

Just one day!! Yikes! If you can eat dinner out during sunset —- Go to Breezes in Somerset, Sandy Parish at Cambridge beaches resort. Location closer to dockyard than other restaurants. Just take a taxi both ways. (You could bus it and walk but not easy to find). Save time and frustration.  

A view of Cambridge Beach cottages from the beach where the restaurant Breezes:

  

If you want to sit on a beach go to Elbow beach. (Rent Umbrellas & chairs, food, drink), bring own or rent snorkels and rent kyack to get out to reefs right off beach. If you eat at restaurant let beach rental and restaurant know you are doing both and you will save 10% off. Expect food and beverages to be high/double of what you are used to because everything is shipped/flown in except seafood.  
Or if you want action/adventure and local info —- Sign up for the Hidden Gems tour pay direct versus through cruise to eliminate addition charge of $50. Read the reviews and bring towel and footwear – sneakers you don’t mind getting trashed or water shoes/sandles like Tevas. They provide everything else you need.