Truly a interesting proposition, as may routes have their inherent scenic attributes. However, having ridden most of the routes outlined in these postings I find it difficult to pick one single route. Being a Californian I would think one would tend to select the ocean or rugged mountain vistas, however; my selection would be SF Zephyr, before it transited the Rockies on the Rio Grande, when after Denver it traveled north and west across Sherman Hill.

I still am impressed by the 'amber waves' in Colorado and Wyoming and what seemed like miles of untouched land. No it is not grandeur, but open space that gets my vote. I took that trip almost 35 years ago and the memory of traveling outside of Green River and watching the antelope run away from the train in what seemed like a mile long line of bouncing anamals with white tails clearly visible as they ran from the train is a memory that ranks up there with Donner, Shasta, Glacier Park, and Southern California/Washington water spots.

And yes the Sunset with its desert get quite boring after 5 or 10 hours, but the mirages leave a lasting impression, so maybe it needs to be on the list.