Don't be surprised when the beach fills up. Take an extra few minutes and walk further east when you arrive.
Skip lunch in Bermuda and eat on the ship. Five of us spent $120 with tip for burgers and colas!
I have been to the fort in Old San Juan and would recommend it if you've never seen it.
The beach is nice. Be warned that the beach here is narrow, so if the tide comes in you don't have much room to back up your chairs. Also, be warned that it is not uncommon for women to sunbath topless on the beach. Also, Orient Beach is directly next to a nude beach, COMPLETELY nude, and it's not uncommon for the guests at that beach to walk to the boarder of Orient Beach.
I'd suggest taking a beach excursion. The best time I ever had was on an excursion on the Norway. It was a short tour around the island, a lunch of cheese and bread and wine, then a few hours at a beautiful beach. Calm waters, wide beach. Yes, it was topless too, but so much nice than Orient. I wish I could remember the name...
You can bring back to the US up to 5 liters of alcohol as long as one is locally made.
Then there are the jewelry and watch stores. Anything you could possibly want can be found here at an exceptional price. The best part is that US citizens can bring up to $800 back into the states duty free, but up to $1,600 if the purchases are from St Thomas.