BOS-MYR O&D is 138 per day (as per faremeasure.com). It is marginal numbers to start daily service on. It might work. Look at the O&D for BOS-LGB in 1999 vs today. With B6 marketing the route in BOS I think it would expand the route to a profitable level.

As far as going out of JFK, I think it would be a great route for B6, even with the competition from Spirit running that route out of LGA. It would be great to start in June in time for the summer peak season.