Phillip, my experience on the Transcon through Flagstaff was exactly as yours. Driving between Williams and Kingman, there were open spaces where you could, from a distance, see several trains coming and going. Flagstaff is a horn-free zone now, but not when my wife and I spent several days at a hotel along the old Route 66 near the depot. As former military and lifelong train fan, I slept through it but she
couldn't.
On several occasions, I saw various trains 'racing' on parallel tracks going in either direction. When we went to the Route 66 'museum' in Kingman, two trains passed by just in the time for us to get into a parking space, me grab my camera and walk the short distance to the spot. Then another came by less than 5 minutes later.
The are is for freight like the NE Corridor is for passenger trains, in regard to frequency. More so, in some cases. Every train fan should go there at least once to marvel at it all.
-Lee
Flickr photo set of my On30 layout