First, let’s get this observation out of the way:  the Grand Canyon of the Arkansas is in Colorado, and the Grand Canyon of the Colorado is in Arizona.  Maybe they could start over?  Now, about the postcard:  unmailed E.C. Kropp 32571, with a pencilled notation about the bridge in the message area.  “The D. & R.G.W. Railroad and the Arkansas River run side by side…”  Grade: 4