Lived in the BVI for 6 years, loved it. If you’re coming from Miami you’ll have to transfer through Puerto Rico. St Maarten have direct flights from Miami, St Kitts I’m not sure about. Nevis is a ferry ride from St Kitts or a flight from Antigua.
Had trips to St Kitts and Nevis & St Maarten
BVI is great if you want a fairly chilled out time, but can be expensive as a tourist, really depends on what you want from your trip. For a total getaway, do nothing but read a book on beach holiday then consider Anegada. Not much to do there apart from Beach, Snorkel, drink rum, eat lobster. Hotels – Anegada Reef, Potters. You can get there by ferry or air via Tortola
North Sound on Virgin Gorda (where Necker is) is very pretty and fairly laid back with easy access to the rest of VG. Hotels Bitter End Yacht Club £££, Saba Rock ££ or Leverick Bay £. Again via Tortola. Good diving, good food, some hiking.
Tortola had a lot more going on, Sailing, diving, more nightlife, lots of expats, great beaches, try and avoid cruise ship passengers that can double the population on a 3 ship day. Hotels. Frenchmans Cay ££, Fort Recovery £££, Village Cay ££,Long Bay ££, Sugar Mill ££ Tamarind Club £, plus a few others.
All the beaches in the BVI are great although I’d avoid Cane Garden Bay (cruise ship passengers are bussed in there and the beach can turn into a sea of overweight, obnoxious Americans, demanding beach service from the bars)
If you have any specific questions, fire away and I’ll see if I can help.