Suggest that you fly into STT and consider chartering from a base on St. Thomas. CYOA (10 minutes from airport) has a great fleet of new boats, monohulls and cats. You can forgo the time and cost of taking a commercial ferry and sail your boat yourselves to the BVIs and maybe enjoy St. John along the way. Olga's Fancy is a great place to overnight enroute. They have a pool and a 4 minute walk to restaurants, deli and also CYOA.