For best info on SVI sailing, I can recommend you contact Jim Veiga at Sail Caribe. Bareboat charters out of Fajardo, PR
. Passage from Fajardo to Vieques or Culebra is much more comfortable than from St Thomas. You can do a week of sailing, best beaches in the caribbean, snorkeling, some laid back hangouts and restaurants, and no customs to waste time on! If you want to do all three (BVI,USVI,SVI), maybe Jim can arrange a downwinder and return the boat to Tortola for you.