I've enjoyed several 3-day trips (no sleeper) from the midwest to the west coast a great deal. Apart from the scenery, there's the honesty and storytelling ability of the landscape. Travelling through towns and seeing what the townsfolk seldom see. The weather sweeping across vast plains and mountain forests.
If you know some of the history of areas you're moving through (which is very easy to do these days), no audiobooks or iPods needed. Fellow passengers may have remarkable stories to tell - even with no words spoken. Oh, and that 'no smoking inside' thing? Don't take that too seriously, keep an eye open.