Hey Tank,
You aren't going to believe this but.....Foothills Blvd all the way to the south end is the start at Yuma. You have to get a permit to travel on it since you are out on the Barry Goldwater firing range. To get the permit you go to MCAS on 3E past the main gate to the next gate and it is open, the fence to MCAS encompasses around some trailer looking offices. But were those temporary buildings are ( been therer over 30 years ) is where you get your permit at. I have traveled it a few times back in the late 60's and early 70's as a kid. We came out at Ajo and drove 8 back to Yuma. Hal