On a path from Eureka, KS to Sipapu, NM, you could hit the Gypsum Hills near Medicine Lodge, KS and ride the open range of Ted Turner's huge buffalo ranch.
In 2006, I enjoyed a ride with the Backroads Touring boys through the area. Here is their ride report from that trip:
http://www.adviaweb.com/btk/06_10_06/index.htm
I do recommend Buster's in Sun City for a lunch stop if it fits for you. There is NOTHING else in the "town".
Btw, you boys are going to be HOT in late July! Bring lots of water.
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