Ok, here comes the maps and Dick you started it.
http://snr.unl.edu/soilmap/NebraskaSoilMap.asp# Being a native Nebraska goober, I always considered the sand hills being zone 12. Where NN is located, I always assumed those were old river dunes from the Platte which is shallow meandering river and you have enough soil on top where you can grow corn. My folks always told me that they could never grow crops in the true sand hills because the Nebraska wind/sand combination cuts down the seedlings.
NN is a nice piece of property and we should get to play some fast and firm conditions. When I played the original 9, the greens and fairways were fuzzy. I always assumed that was because they were trying to save on their irrigation costs. One interesting hole stuck out in my mind was a shorter par 4 on the SW corner of the property, with interesting (grass bunkers) placements. Now that I think about it, I don’t believe they every dug any bunkers out there? Jim, is my memory correct? Or can you tell anymore?