Ron,
For whatever it's worth (I guess the interest of those who look in at Golf Club Atlas), the history of Prairie Club is kinda interesting...
I can't remember the exact year right now - but it must have been 2002 or '03 - when I travelled down to Valentine, Neb. with Rod Whitman to interview with Dr. Clive Trimble (the original visionary for the project, and then owner of the ranch at what is now Prairie Club) to design/build a single course there. I can't recall - or if I even knew at the time - how many architects interviewed either, but I know Gil was one, because he landed the job.
Dr. Trimble - for a number of reasons - transferred the project, and ownership of the ranch not long after, which led to Graham Marsh's and Tom Lehman's groups creating the two existing courses there, at Prairie Club; Gil (and co.), as you know, was "relegated" to creating the Horse course.
I don't know the current status of "Old School"; but, again, it's kinda interesting to look back now and recall that Gil was originally slated to design/build the first course at Prairie Club, for Dr. Trimble.