A quick, cursory google search brought up several unofficial news sites stating in various ways something to the effect of: "Eshelman bought the Elk Mountain Ranch in 2005 under the belief that he could control access to all the public land it enmeshed" and "When I bought the ranches, I was assured that corner crossing was illegal,” Eshelman said. “I went to BLM websites, and it said definitively, corner crossing is illegal.” That tells me Eshlman had at least some increased interest in the property due to the access situation, and I think it is a fair statement to say he was willing to pay more for it, due to him believing he could control access to the public land the ranch surrounded.
The first pdf document that comes up when using the search query "corner crossing" on BLM's site pertains to BLM land in Wyoming. From that document:
"What does the law say with regard to corner crossing?
There is no specific state or federal laws regarding corner crossings. Corner crossings in the checkerboard land pattern area or elsewhere are not considered legal public access."
Not only is that not "definitive" it doesn't even make sense according to how US law works.
