'Across the pond'-Breagh01
I can't believe they'd use a 737NG on a routing via St.Johns. It would make more sense to route via KBGR where the pax and crews can clear the drag of U.S. Immigration and Customs while the A/C is being cleaned, refuelled and catered therefore entering KBOS, KJFK or KSFB as a 'domestic' flight.
KBGR or Bangor,Maine used to thrive on those kinds of op's when most UK Charter carriers used B757's on the US/Caribbean routes. Carriers like Air2Bob, Britannia, Airtours, Monarch all had a bunch of crews floating through KBGR which meant you always had some precious 'Standby' cover for both cabin crew & flight deck.
Just a thought.