This past summer, I took the Coast Starlight from Seattle to Monterey with my wife and kids. I
loved it. It's hard to convey how different it is from flying.
Whenever I fly somewhere, especially these days when flying is such a miserable cramped experience, I always feel like my vacation starts after I endure the entire airport + plane experience. The whole travel part is in the same "chore" bucket as packing, finding a pet sitter, etc.
With a train, the second we reached the train station, it felt like the trip had started. Many train stations are beautiful historical buildings right in the heart of downtown, so you're already experiencing a city and cool architecture. The staff and the whole process is very laid back without all of the security theatre nonsense of the TSA. It's about as formal as going to a play.
Then you get on the train and you get to completely relax. I brought a book to read and some stuff like that, but I spent more than half the time literally just looking out the windows. Train tracks don't need much surrounding infrastructure, unlike freeways, so their routes often go right through little towns, along the coast, etc. You'll be seeing into people's backyards, storage area for businesses, farmland, everything. It's like a perfect cross-section of the entire US experience.
And it's quiet. No constant roar of engines like a jet. You can talk at quiet volumes. The observation car feels like a chill coffee shop with an amazing always-refreshing-itself view.
Time slows down. You watch the sun set and then watch the light leak out of the sky. You go to bed and get rocked to sleep.
Taking a sleeper car train ride isn't cheap in terms of time or money, but I would highly recommend it. I can't wait to do it again.