There are also all sorts of Amtrak promotions for additional points, so you will get even more points. Check this board or your email for added promotions.

Bus or car? In the Northeast? I'd rather get run over by a bus or car than take one for 2+ hour commutes twice a week.

ETA: You could also take Amtrak part of the way (as there is a gap along the Philadelphia-Washington route where there is no other passenger train except Amtrak) and MARC or SEPTA trains the rest of the way. That would be kind of painful too, though.