C.H.
I have been to Cayman, the BVIs, ST. Vincent and the Grendine Islands. I just got back from St. John and there are tons of villas! Go to http://www.caribbeanvilla.com/ You actually fly to St. Thomas, rent a jeep and take a short ferry over to St. John. The sand is soft and the water is clear and beautiful and the beaches are not very crowded at all. We stayed a week and went out to dinner half the time and cooked half the time. The cost of food though is about the same as going out.
You do not need to pack resort wear, be casual...you are on island time.
Cayman is great for Scuba diving if yall want to do that, not sure about villas there. Stayed at a hotel.
Fill free to email me with any questions.