its a problem even getting a cab to go back to the airport from a suburban (RF) mall
you could call a local cab company and hope- but who knows if they will even show up or if you will find them
forget about GA- it is "downscale"
but- for only $25 to $50 an hour you can hire a "black car" to pick you up, drive around, wait for you, and bring you back to JFK - no hassles and a safe place to leave your purchases while you shop
you can make RF in 30 minutes in no traffic
but it could be 90 if traffic is bad- or if it rains- or snows-or construction
i live 45 minutes from JFK (at 4am on a sunday morning) but it has taken me 3 hours, too!!
you could probably take the airtrain to jamaica to LIRR to penn station, manhattan in less than an hour
and macy's- the worlds largest store- is right across the street!!!