easiest way to get to Penn station from JFK is to take AirTrain to Jamaica LIRR train station, then LIRR at Jamaica to Penn Station. go to http://lirr42.mta.info/sfweb/faces/index.jspx to find train times from Jamaica to Penn Station. the AirTrain is not hard to use at all. the main line runs around the terminals and right to Jamaica. VERY easy.
easiest way to get to Penn