Secure a vehicle rental.
Provision at RTW or Bucks when you arrive.
Bring your snorkeling gear unless you plan on renting some or just using their stuff on your excursions.
We did a day trip to Anegada with Dive BVI, they also do a booze cruise to the Willy T and White Bay. I believe they also have another set cruise to 2-3 snorkeling spots.