I just returned from a trip to San Diego and rode out and back on Amtrak's Southwest Chief and Pacific Surfliner. I had been wanting to ride Amtrak for a long time, and when the opportunity to be a delegate for my church at our national conference came up, I jumped at the chance.
During daylight hours, I spent much time in the full window observation car watching the scenery go buy. My photo taking in this car was not ideal as the windows were extremely reflective.
We passed a number of historic places including Raton Pass, Glorietta Pass, and followed the route of the Mountain Route of the Santa Fe Trail in Kansas, Colorado and New Mexico.
I found this method of travel was great for meeting all sorts of people. I enjoyed chatting with all sorts of travelers, even some foreign folks who were on a multi-week train trip.
We were able to get off the train long enough at several stops to allow me to explore around the depots. This was especially true in Albuquerque, where I had over an hour to explore going both ways.
The only negative aspect was the fact that I could not sleep effectively in the coach seats, but I was not alone in this respect.
If you have time for a more leisurely trip, consider Amtrak. While they might not offer the same level of travel as in the heyday of passenger travel, it is neverless a great way to travel.
My photo gallery: http://ke2013.smugmug.com/gallery/8700664_VVdu3#575022796_L4Aop