The million dollar question is why with the maps, sketches and directions did they directly confine their search to one particular area? They put a major effort into those trips and stalled there. What was it they couldn't figure out from that point?
That is the question, isn’t it? Especially since they were so close to the original source of information.
The evidence tells me that Reiney simply didn’t listen, didn’t care and\or didn’t understand what Waltz was telling him. Apart from Waltz scolding Reiney for not paying attention on multiple occasions (Sims 112) Waltz told them he was going to: “stop at the cow-house and point out the way from there” (Sims 112, 115). Unless I am missing the obvious, the cow-house was SOUTH of the mountains.
Hermann Petrasch talking: “We traveled eastward across the desert from Phoenix......... We walked around the NORTHWEST END of Superstition Mountain and packed all of our supplies to the area of Weaver’s Needle...." (Tom Kollenborn, Julia Thomas Schaffer). Although Herman is speaking in first person, I believe he is recounting the first trip Julia and Reiney made. My point is, Waltz tells them to enter from the SOUTH and they enter from the NORTH.
“Like the rest of us, he (Herman) was baffled only by Reiney’s IMPERFECT MEMORY of those directions which Waltz has vouchsafed as he lay dying…..(Sims 117)
Glover also concludes that Reinhart simply was not listening and disinterested when Waltz was giving him the directions – (Part 1 pg 154, 178-9)
Just my opinion - FWIW,