It's a good theory. If you believe it's true, what part of the Superstitions seems to have been lessened as a location? East of Parker Pass, West Boulder, Needle Canyon or even Peter's Mesa?
What if they were just trying to get out of the interior, and took that wide'assed valley out to the Massacre Grounds? There is no place in the interior that can be traveled to or from, without passing through ambush sites.
Let's say you were in Aylor's Caballo Camp. Remembering there were no real (maintained) trails back then. You want to get to Goldfield. How would you go to avoid not being packed into a bunch of tight spots? Same question, except now you start from Willow Spring.
My reasoning behind my posts is that if you were coming in from the South, say from Mexico, and you wanted to get to Iron Mountain, it would not make sense to go in at Goldfield unless you had a reason to go to Goldfield first. It would make more sense to travel East across the southern end of the range and go in from there somewhere. So in my opinion, this takes away the majority of the South East part of the range (East of Miners Needle) from being the location of the LDM.
I've long thought about the massacre grounds murders, and have arrived at a couple conclusions as to why they ended up there. I remember reading they tried to get out of the mountains in one direction, were turned back and would up trying to get out at Massacre grounds where they were killed.
My thought is that they were headed out of the range by going past Weavers Needle, got trapped in a canyon by the Indians, and turned around. Their only other exit would be through the Massacre grounds area. Going East wouldn't make any sense. They were headed south past Weavers Needle because they were working directly North of there, and that was the quickest route out. When your running for your life, you don't think about the best way to do anything, you find the quickest way to get away from your pursuers.
Another thought I had was that the Indians approached them from the North, and forced them to travel towards Weavers Needle, then the Mexicans somehow managed to get around them, heading towards Massacre Grounds where the Indians were waiting, expecting the encounter there.
I find it highly un-likely they headed straight for Massacre Grounds.
Something else to keep in mind, that I don't think has been brought up, is that the Mexicans were caught coming off of Bluff Springs mountain, and headed South as going North would run them into the Indians, and South was the quicker route out of the mountains.
I'm no expert on any of this, just sharing some of my crazy thoughts