Mith,

I'm not sure what would happen if you handed the conductor a ticket from Lewistown, while boarding in Paoli. In theory he should accept it, since technically you paid to travel further than you really did. However, if Amtrak has caught people doing this before, then they might have created some rule to stop that. My guess is that there is no such rule, but I don't know.

On your return however, there would be nothing that Amtrak could do. They would have no way of knowing that you got off in Paoli, even though you were ticketed to Lewistown.

As for picking up the tickets, it wouldn't matter where you picked up the tickets or when you picked up the tickets. You could pick up the ticket a week before in Philly if you wanted. I would not however recommend waiting until after the train has left Lewistown to pick up your tickets. It is possible that the computer might cancel your reservation once the departure time has gone by. I'm not sure how fast that happens.