Hi Jay - We did something similar to this on the "Winifred". We had the boat to ourselves, just us and our 2 sons. We sailed along with another similar boat with our friends, their 2 kids and another couple. It was a great experience once, but I wouldn't repeat it, but I'm very glad we did, as it was a unique experience with some beautiful views.
We learned from this full daysail that we prefer faster catamarans vs. the slow, tacking sailboats. Catamarans are so much more roomy while a sailboat feels cramped. Also, while sailing back, it got pretty rough in between St. Thomas and St. John.
The currents were strong where we dropped anchor and because it was a sailboat, we couldn't get very close to shore compared to the "cats". It was a lot of swimming (which I enjoy). Thankfully, my sons are very good swimmers and could handle not only the current, but also the long, long distances to the sailboat, but there were quite a few who wouldn't get in the water and wouldn't swim the distances.
The food was the pits, but the Captain's mate was such an interesting, wonderful person, that we were just happy to be there and experience it. I think I could live in the water and the hardest part for me was having to get out of it for the long sail back to St. Thomas.
Any questions, just ask.