Actually you can do it without wasting a day for the ferry or staying on St. Thomas. Assuming you arrive in time for the last downtown ferry and you very likely will unless the plane is quite late --indeed you can call Smith's Ferry and they'll hold it for you a bit or send a taxi for you. I would d...

My answer to your question would be to take the ferry, but be aware of it's limitations. The "see the BVI" trips cover too much ground unless you want a general overview with a stop at a few of the tourist highlights. It reminds me of my wife and I's introduction to St. John in the early 9...