I agree that the river and the A&NM were probably drawn in as an after thought without any real measurement. I've found that rivers and streams are usually off on most of the maps that I have viewed except where a bridge is drawn in. I was kind of surprised that the A&NM looked so far off though. I would say that the MSRy mainline is drawn accurately. The wye on the other hand is somewhat off compared to the grade on the ground. It is generally in the right location. The head block locations look pretty good but the wye tail seems to be twisted a bit too far to the west.
Dave