Nice sleuthing! I thought about smudging those dates, but I wanted to leave you guys
something you could work with, and sure enough, you found it! You're correct on all counts, all the way down to the name of the Wash where Tom Mix rolled his Cord Phaeton convertible, and died at the scene from a broken neck.
Old Tom most certainly isn't the only person who has ever driven much too fast on that road. The Pinal Pioneer Parkway is a very pretty stretch of two-lane highway that shoots straight as an arrow through a cactus forest. There's little traffic, and wide open spaces that beckon you to fly. In one particular year--2011--the fastest 5% of the vehicles using this stretch of road were clocked at an average speed of 88 mph, which made the Pinal Pioneer Parkway, during the course of that survey, the fastest road in the west! (Actually, it was the fastest road in the entire USA, which is truly amazing!) AZ 79 between Florence and Oracle is what us deep-rooted Phoenix natives have always called the "old road" to Tucson, since it pre-dates the Interstate, and because it still has the look and feel of Arizona the way it used to be, before the mega-population boom turned Phoenix into a major modern city. If you're headed from Phoenix to Tucson, or vice versa, it takes a little longer on this back road (unless you're one of those crazies in the fastest 5%!) For everyone else who's
not in a hurry, it's a
Scenic Side Trip--an easy alternative to Interstate 10, SST#8 in my book-- that's well worth considering!
Rick