Time to get started to look for the Cody lines in Kansas. Buffalo Bill (William F.) had a home in North Platte, Ne and he had kin in the area I am sure. I would also suggest that you search for families out of the east who moved into Kansas if that is where the family settled first.
The families that I have talked to here in the east(Georgia) thought that William F. Cody was kin to them but their family came from another line. There is more than one line on Cody's in the U.S. so you will have to try and get to the census (free for the most part on line) and see if you can run them back east.