Reply #2: You are smart not to drive into DC

[MajorChode]

It's a big hassle, especially during the week during normal office hours.

My experience with Amtrak is it's more like buying an airline ticket. You buy your ticket for a specific train at a specific time. Amtrak does sell passes, but I think it would be too pricey unless you are making several trips. You can buy your ticket at the station right before you board. You might pay a little more than buying advance tickets, but not much in most instances.

There are a lot of commuter trains that serve DC. You can drive to an outlying station, park, and ride the commuter train. Just be careful about driving to the last station or two before downtown, because the parking lots fill up quickly during the week in the morning. They aren't as bad at most of the stations that are farther away but some of those parking lots fill up too. There's also a lot of options for buses.