Coworker said that time is the luxury item. Unless your car is following exactly a regular Amtrak route, at some point you get decoupled in a yard and passed off to another train, which can take hours. Basically a layover. So it sounds like it can easily become a multi-day thing to get somewhere you can get in like 5 hours by air.

But yeah, if you have the time and inclination, it seems like a pleasant way to go.