When I lived as a poor vagabond couch-surfer in China, I did almost 100% of my traveling by train.
I'm convinced there's no better way to travel.
When you travel by airplane, you're pretty much rapidly moving from huge city to huge city. You miss everything in-between, from the terrain to seeing how people outside of the cities live.
Even driving from one place to another, you're confined to the freeways. You see a little bit more, but you're still in this weird world which was built around the freeway.
When you travel by train, however, you follow the lay of the land. That takes you into some interesting, fascinating places. Combine that with the fact that you can get a sleeper car and food, and it's an entire experience, not just a rush to get from point A to point B. I spent most of my time reading and looking out the window. It's bliss.