Agree 100% with Terry. Eliminate the ferry ride, family standing in lines at C&I, and additional taxi ride to the yacht base. Under best of circumstances and with no flight delay, the ferry option won't get you to your boat til about 6 pm with sunset at about 6:30 pm in March. I doubt the captain will take you for an evening sail.

From Redhook you'll have time to enjoy a short sundowner motor/sail to a St John anchorage for the evening, then a 30-45 minute run the next morning to Great Harbour or West End C&I where only the captain will need to present himself.