As someone who goes up to NYC somewhat frequently on Amtrak I cannot stress enough how much of a difference maker booking a few weeks out makes. You can do it for $40 or less round trip with the right planning. Something I do is if I think I’ll be going up during a certain month, I’ll just book it for an estimated weekend and bank the tickets. If I end up having to adjust or push the trip later, it may cost a little bit depending on how close I make the change, but I can move them and still pay less than if I made the reservation last minute.