transfer is pushing it.
Some years ago, I booked my wife and a number of Girl Scouts on a CPH
itinerary, because that was the only way to keep the cost under the required minimum. If I recall correctly, the CPH
flight landed at 6:35 (Eastern), and the LGA
flight left at 7:35. I had flown the LGA
flight numerous times and it had never been less then 20 minutes late for me.
Needless to say, that day the LGA
flight left 3 minutes early, and my wife and her scouts missed it by (if I recall correctly) 14 minutes. They ended up staying in LGA
overnight, and I paid dearly for it.
You are suggesting a -3 hour transfer, but it's during rush hour. So, do you feel lucky?
(If it were me, I'd go direct from JFK
as "a new airport for me" isn't worth the trouble. Your mileage may vary.)