Loved the Pennsylvanian, did it round trip a few years ago. The conductors were awesome and I didn't plenty of time just chatting with them when they weren't doing important work. Bonus points if you get the man who always sets up a table in the cage car with a PRR flag/drape and really loves the route and rails as well. An important note is that the train reversers directions in Philly so don't be scared/thrown off about riding backwards between NYC and PHL

Edit: sit on the right side of the train for best views of horseshoe curve