Originally Posted by emika

California Zephyr is a pretty good route- lots of beautiful scenery and it goes to the bay area which is a great place to visit too if you decide to do the entire route. Sleepers are a bit expensive, but worth it for the meals and shower.

I haven't done any other long distance routes, but everything I've seen always says that California Zephyr is the one to take if you want to do it for fun. The Rockies and Sierras are breathtaking; I've done it when it was snowy and when it didn't have any snow on the ground and enjoyed both.