The train can be fun, but you need to be a social person. Bring some cards, a hidden flask of your favorite beverage (if you are that type of person), and you are set. Meet a bunch of nice people, have fun, and enjoy the experience. Also, bring a laptop, some headphones, a couple DVDs, and an extension cord if you get bored.
One key to me is how long you get an observation car (windows all over, swivel seats, and movies playing). Camp out there, watch the scenery and talk to everyone you meet. Heck, I usually don't even bother getting a seat, as the observation car lets you sleep there at night.
The meals can be good, but expensive. The sleeper comes with fee meals, so in the end, a sleeper might not cost much more. This is especially true if you just get on and ask if they have an available sleeper. They are bringing it anyways and are often willing to cut you a good deal just to fill it up.