I don't remember seeing anything that intrigued me.
If that's the only place they want to go, they could just take a cab. We were on a tour that we weren't really enjoying by Maho (we had zero interest in Maho and we were there b/c that's where the tour went) and nearly took a cab back.
They just need to keep CLOSE track of time, realize that getting out of the Maho area can be slow-moving, and take traffic into account. Wear a normal watch that won't update to a timezone the ship might not be on, too.