I recently used an amtrak rail pass with a buddy which was my first time on the train and a great fucking experience. If you wanna take a very interesting vacation trip, I heavily recommend buying the railpass ($500 for 10 segments in coach) as long as you don't intend to circle the whole US. I'm good at sleeping in vehicles so im biased, but if you can snooze on a plane you can pass out in coach of amtrak. Bring a blanket and/or coat because the train gets cold, and bring a pillow. Don't be afraid to lean the chair back though, there is so much legroom that the person behind you would have to be absurdly tall to be cramped. Ask first of course, but still. Also bring noise cancelling headphones if you have them, or if not then earplugs. The seats are SO much more comfortable though, oh my goodness. Also as I mentioned, the legroom is glorious and this is coming from someone who is quite tall. Depending on where you're going, see if you can take the more scenic train/time of day. Like, I took the train from DC to Indianapolis riding the Cardinal which goes over the New River Gorge in the Blue Hills Mountains, so if you're riding that route I recommend starting early enough that you get to see the beauty of the mountains. The thing about the railpass is that once activated for the first trip, all segments must be used within 30 days so know where you're going. I went around the northeast in a big loop: Boston (starting station for many trains in the northeast. Earlier stops have more seat choices) DC, Indianapolis, Chicago, Pittsburgh, Philadelphia, and back to Boston before going home. Over the course of that, I realized that the experience of a 6 hour train ride is the same if not significantly better than a 2 hour flight to the same place because I don't have to go to an airport or be on an airplane, also because trains are based. My longest ride was DC to Indianapolis which was 18 hours, but comfort and a small edible let me sleep through like 9 of that and the other 9 was spent starting out the window at the beauty of the mountains and taking pictures. Overall, amtrak is an example of the travel being part of the journey not just the destination, however cliche that is. If you really need to be somewhere that's a 4 hour flight but a 40 hour ride with 10 hours of layover on amtrak, do the flight. But, if you're going somewhere in the northeast corridor or you've got a little extra time on your hands and want something cheaper, comfier, and overall more fun than a plane, ride amtrak.

Note: Someone else gave a great tip about upgrading to a room last minute to save money which I know nothing about. If you're using a railpass purchased after July 1st 2021 then you cannot upgrade any of your rides on that pass. Also because of covid they made dining outside of the western most area of the US shittier so it's not worth it unless you're starving. Bring a fat bag of granola.