I found some $216 SEA - EWR.

However, SEA-Philadelphia 30th. Street Rail Station, PA (ZFV) is only $189. Can I book that one & ignore the train segments? I wouldn't mind going to Philadelphia for that price, but it would be even nicer if I could just hang out in NJ for a few days instead!

Anyone have any ideas if the EWR-SEA return flight home would be canceled if I don't do the train segments??

Also, does this train have an option for business class? How would you book that? Seat selection only told me "seats can not be reserved on this part" and indicated economy section.

Anyway. cross country from SEA for less than $190?!!?!?! Whoooo!!