BTW, I've booked a couple of Amtrak trips for my DD in the past two months and I've learned this about Amtrak promo codes--first, they require an advance purchase (either three days ahead or seven days ahead), and second, the restrictions that are stated on the code are often not ALL the restrictions on the code.
For example, I just booked a trip up to Boston for my DD and DH, and I have a code where if a teenager is making a train trip to visit a college, their companion gets a free ticket. Great, right? The offer came with two pages of fine-print restrictions. Online, Amtrak's site said it was taking the code, but it wasn't right. I called Amtrak and after much discussion, it turned out that the code would not work on Acela trains AND it would not work on any trains other than the lowest, lowest demand times. So they couldn't leave Boston on a Sunday evening--the first train they could take using that fare would be around 9:40 Sunday night, so they'd get into NYC around 3:00 in the morning!
They'll be taking Greyhound home.
Also, remember there's an AAA discount of 10 percent. Good luck!
Best,
Wacky