Originally Posted by
LaserSailor
Correct.
Amtrak >> NJT >> Airtrain.
Time on the train with a companion (per OP) is wonderful compared to schlepping through airports, even with nice lounges.
NJT runs trains to EWR about every 10-12 minutes during day and 30 minutes late at night. Fare about $15. Watch both depart and arrival times on NJT, the Long Branch one gets you to EWR quicker for example.
If you spending OPM you can get there a bit quicker taking a LYFT/Taxi from Penn direct to the terminal for about $100 fare - 30 minutes total
A train ride from BOS, you are at least half way to Europe already. You would waste a good chunk of day spending on trains.
Acela is also not significantly faster in travel time than non-Acela trains due to poor infrastructure.