What airport do you have to fly to? Do they have an airport or do we have to fly to another island and then ferry to T & C?
Most people fly into Providenciales - Provo. Airport code PLS. It's a smaller, older airport (4 gates IIRC) USAirways (among others) flies there from Charlotte. If you go through Chicago, American does also. (although now isn't that the same airline...lol) I think there's limited international flights to Grand Turk also. The cruise port is there so I've heard the beaches can be crowded.
Travel to the Turks and Caicos Islands by Air Turks and Caicos Tourist Board
It's significantly better diving than St. Thomas. Some dives at the more remote islands are better than Grand Cayman. Dayboats go to them (French Cay, West Caicos) from Provo but it's about a 45min. boat ride. There's no shore diving off Provo but there is a little off Grand Turk - there's a wall that's accesible from certain entry points.
Grace Bay Beach on Provo is one of the nicest beaches in the world - rated that by many travel publications. It's also expensive to stay on the beach because of it. The AI's are Beaches (kid-focused) or the Verandah. There's also Club Med Turkoise.
All three locations (St. Thomas, DR, T&C) are in the hurricane belt. Anything that impacts the Bahamas could impact T&C since they're nearby.
You might look at Curacao or Aruba - or Aruba then a local flight to Curacao. Flights/connections are better and they both have nice beaches. I don't know Aruba but on Curacao most of them are also dive sites so have a dive shop on-site. Both are below the hurricane belt so infrequently affected. Flights might be too long from MI for a few day trip though. Really excellent shore diving on Curacao - in some areas I thought it better than Bonaire - it's certainly more diverse.
South of St. Thomas there's dozens of wreck dives.
http://www.blueislanddivers.com/02_sites/divesites.html Also on an all day trip you can dive the signature wreck in the BVI's - the RMS Rhone - with Cruz Bay Watersports.
http://www.divestjohn.com/scuba-diving
Nice beaches on the East End of St. Thomas and it's quieter out there also. Charlotte Amalie has the cruise port and judging by the number of gated/patrolled resorts we saw crime must be an issue on the island. In fact the counter person when we checked in for our flight warned us about that. We went thru St. Thomas (stayed over a couple of days) to the BVI's so it wasn't an issue for us.