I'm in a suburb of Kansas City. I raise New Zealands and Std Rex. New Zealands, I usually stay within 200 miles which gets me to Omaha, Wichita, Topeka, Columbia. For the Rex rabbits - which are much harder to find - I post in the major cities in KS, MO, NE. (Those ads have pulled people in from Colorado and Oklahoma, too. ) I guess I post in about 15 cities total, depending on NZ or Rex.
Why out so far? One day I did Omaha on a whim and was surprised at the number of responses I got and the rabbits I sold. So then I kept going further out and kept getting surprised. KC is at the intersection of I-35 and I-70...major North-South and East-West interstates - pretty easy to get to.
Since all it takes is time, post where you want and just keep track of where your responses come from.