That's a pretty good rate. We are in Hershey and can train or drive to PHL in about 2 hours. We booked over a month ago for Dec-Jan time frame. Yes, it's AA but have chosen to overnight at Marriot that is connected to PHL airport and go nonstop to SXM early next day. We will likely stay at hotel again on our return trip to avoid late drive or train back home that night.
I'm sure you will enjoy your return to SXM and they will appreciate your return as well.