Admire the most impactful Virgin Islands port city as your ferry lands in Cruz Bay.
Spend an evening walking around Cruz Bay enjoying a couple of drinks at the 20+ safe walkable spots.
Depending on your preference, take the mostly flat hike to Salomon Bay and Honeymoon Bay for some beach time. If you want to take a taxi back to Cruz Bay, you can continue to Caneel Bay and catch a taxi back there. Or, take a taxi to a northshore Beach - Hawksnest, Trunk and Cinnamon are the easiest by taxi, and the easiest to catch a ride back.
Cheers, RickG