How "quick" of a vacation are you looking at and, without trying to pry, how much of an issue is cost?
Those things asked, depending on your answer to the first part of that query, if time allows (not to mention your sea-leg disposition), I would opt for not staying on the island, but chartering a catamaran. Know some people down there who will set one up nicely in, to start, about a 57', with every luxury imagineable. Then you can simply go from cay to cay/isle to isle, or anyway the wind blows...it's amazing to stay on a boat and see the area from that. Pick up anchor and go to off-the-beaten-venues and then, if you like a place, drop anchor and stick around for awhile. If you don't like it, no worries, go somewhere else. If you want to stay on land for a while, no worries either - spend the day there, the night, the next morning, wake up and your vessel is ready to go when you are.
Not a good idea to bare-boat it down there unless you're very well-acquainted with navigating the waters - quite tricky in spots, many protected areas as well. You can get a nice sized cat with a chef and captain, say a week's worth of food - which you pick ahead of time, so you're not at their mercy - and a first hand account of the whole area, for a very reasonable amount.
Put it this way, whenever I go down to any portion of the Virgin Islands and points south-east, I no longer stay on land - always either chart, or if I'm feeling like busting my ass - captain my own boat down - far nicer to let someone else do the work though.
