We've already bought our tickets for December, so I don't think you're too early. If the prices drop significantly, we can buy the cheaper ticket and get a credit to use on the return flights, which we have not yet booked.

Cape Air has been relatively reliable. One time the checked bags came later because the plane was overweight and once we were moved to a later flight. In my opinion, your best options are through SJU on Jet Blue/Cape Air, either one ticket or separate tickets to SJU and then to VG or Beef.

If you have five people, Cape Air coupons are likely to save you money to Beef. Nervous flyers may want to avoid VG. The ferry from Trellis to Spanishtown is pretty easy.