The length of a route will not always equate to it being favourite. I have been on the Zephyr in both directions, and the scenery is outstanding, which makes it my current favourite. I did enjoy the Sunset too, but I have only traveled from west to east on this train. I find the mix of fellow passengers, the staff, my mood, and even the weather all influence my enjoyment of each trip. I am looking forward to the Empire builder, and the Starlight, as well as the southwest Chief on my next Amtrak adventure!
Ed. B)