Two hours should be plenty of time. It makes sense, though, to pay attention to weather forecasts, and if bad weather is expected in DC or NYC, consier getting to DCA and trying to get on the earlier flight (which, unfortunately is at 6am); AA will let you standby for free.

When you arrive at JFK, the walk is kinda long, but it's well marked. As noted by many others, simply follow the signs to the AirTrain platform, look for the signs indicating which train goes "to all terminals," and stay on that train to Terminal 1. It's very easy.