We feel your pain....United changed their schedule and stopped running the Newark/St. Thomas flights during the weekdays (nice of them to tell us too - I only discovered it because someone else here raised the alarm) and the only way to make our flights work with our trip was to fly into SJU - so we had to pay for Seaborne to Beef island for the way down and Cape Air from Virgin Gorda on the way home.

I hate to say it, but I would just bite the bullet and buy the flights...it's really the only option. Even if you could make the St. Thomas flights work with the ferry schedule, by the time all is said and done, you won't save enough to make it worth all the hassle.....