Could need to stand down
If its where I'm thinking of, I've been there very recently - only it was on foot and I had permission from one of the land owner's agents to be there for my work.
The Sacaton Mountain Mosey was an MBAA series race held on various trails in the foothills of the Sacaton Mountains in northwest Casa Grande, west of I-10, and north of SR-238 and nearer-yet, Val Vista Road. As an event, it went the way of Pulstar hubs and Tange suspension forks. That sound like the place you're asking about?
The trails, mostly hilly fire roads and wildcat singletrack moto tracks, are still there. The terrain I saw looked like fun to ride, but not necessarily worth traveling for (i.e, no better than Hawes, Pass Mountain, etc). Its a scenic-enough place, insofar as you don't stare at the open pit copper mine to the south or all the garbage the local yahoos have dumped (not that garbage hasn't been put to good, artistic use at Fantasy Island). Regardless, its private land now, and it'll be a 5,500 acre residential development (Copper Mountain Ranch) soon enough. I'm not a fencehopper, so there it sits waiting for its highest and best use, so to speak.
I replied to your intro thread, too. I'm a Tucson local, and a a bona fide rockcrusher at that. PM me some time if you'd like to meet at the 50-Year Trail or something.
Bike down,
=Jason=