We do roundtrip from rdoney Bay St. Lucia usually for 14 days but have also done it in 10. The best trip was a 17 hour overnighter from Soufriere, St. Lucia to Grenada then worked our way back over 12 days. If it were me I would look into a one way either starting in St. Lucia or Grenada. If time is a constraint you could also go from St. Vincent instead of St.Lucia. I've only chartered in the BVI's once, but I think the biggest difference will be the lack of infastructure and facilities. Large supermarkets will only be found on the main islands and topping off water tanks may be a challenge. I know you can top up in Cumberland Bay, St. Vincent and I would imagine also at Union Island, maybe rhans or seth know of a few other spots. As said you pretty much have to make your own fun at most of the islands. Boat boys will apporach you at every anchorage, they have some nice stuff to sell and if you're not interested a simple "no thanks" is usually all it takes. The currency is the EC and is tied to the US dollar 2.67 EC/ US. ATM's are available on the larger islands. Sailing will be a little more intense, we've hit winds up to 50 and it isn't unusual to see them in the 30 knot range. It is a beautiful area and is worth the trouble to get there. The Doyle guide is about the best one for the windwards, mine is pretty well worn. I'll be heading down Dec 18, for the Holiday charter then 10 days between st. Lucia and Martinique, where Dan and Em are going to provision for the Pacific. Jan. 11 we set sail for the San Blas islands, then through the Panama canal and down to the Galapagos Islands till late Feb.