wow! the first thing i would say, not to amtrak but to a friend, is that they should not have trusted me with this responsibility. and also that if i don't get to ask the audience then i am gonna make so many people mad. well, so many people will be so mad anyway. on to the question.
my most selfish answer would be seattle and the town where my parents live, because i think it would rock to ride a train for three straight days to go visit them. my second most selfish answer is seattle and new york city for the same reason.
but... my shitpost answer? you didn't specify continental united states, and therefore: anchorage to honolulu baby!!! let's fucking go!!!!!
Chicago is important because you get shot on the street I thought