Luggage toting for the Air Train subway route depends on which stations you use. there are elevators at the Air Train end - but most subway stations in Manhattan have stairs only - usually narrow, steep and often 2 or 3 flights. Escalators are fine when they're working (usually) but at few stations and elevators are fairly rare and often out of order.

Sorry - length of trip depends on day of week and time of day. I've done it from midtown Manhattan to JFK in 30 minutes - but if you hit bad traffic/accident it can easily take an hour - or rarely more. Air Train and subway - depending on time of day can be an hour to an hour and a half.