Our trip in March we drove to JFK from RI with no trouble on a wed. Stayed overnight at a hotel with stay & fly and caught the 8 something (830??) flight JFK to SXM for $168. and it was a piece of cake.

Just checked schedule today and saw that the cost difference in leaving from BOS instead of NY wasn't worth omitting the BOS leg. As Bashton said only the 2 hour layover sucks.