I vote for the train, too--if the weather is bad, Amtrak will run but you really take your chances at the airports. Although that LimoLiner looks intriguing--I'd never heard of that, but I've bookmarked it and I'm seriously considering it for my next trip to Boston.

Also, you might as well go straight into NYP and catch NJ Transit from there rather than taking the AirTrain and transferring. Faster, anyway. I appreciate the convenience of the AitrTrain but I have found it to be veeerrrry slow sometimes. Maybe I'm just impatient.