USVI lacks really good restaurants, even in the "town" area. Went to a few and they were lack luster. The best place is surprisingly a little shack right outside the airport where the local laborers eat! Hotel restaurant is OK, but like all hotel restaurants, a little over priced.
Restaurants we hit that I remembered -
Miss Lucy's
Shipwreck Landing
The Longboard
Buy the round trip ferry ticket from the Westin getting from St. Thomas to St. John's. It's cheaper by a few bucks and stops at the Westin instead of the regular ferry stop which you then have to take a cab ride.
Speaking of cab rides, if you have more than 4 people in your group, rent a jeep at the Westin. Cab rides are per person, not per cab. The cabs are pickup trucks with benches in the back for you to sit on. You will need a car to go snorkeling anyways.
Bring sunblock that doesn't use Avobenzone. Use the "kids" ones that uses Titanium Dioxide or Zinc Dioxide for sun block. They are better for you and the coral reefs.
Snorkeling area -
Hawksnest Beat
TrunkBay
Maho Bay
Haulover Bay (Best) They have a North and South, we went to the North. Park on the road and hike in. The beach is 90% rocks so not much place to just lounge around but nobody was there at the time and the reef comes all the way to the beach.
Salt Pond Bay
There's a local market walking distance from the Westin heading towards town (St. John Gourmet Market). Get your stuff from them. Closer in town there are a few smaller markets that is slightly cheaper, like cents cheaper so not worth the hike out. From my time there, I only saw 1 gas station and they close after 8pm so fill up early
Make sure to buy your stuff at St. Thomas. Tax and duty free. Load up on booze and luxury stuff there.
Enjoy the trip!