the TBN classifieds (some response, most not local)
my work bulletin board (no response)
parked it at the end of my driveway (lots of response about my Kubota )
tractorhouse got some response, again most not local
I had one local guy who I think I sold on second teir brands...but in the end I traded it in to the dealer I was buying from. He gave me a good price on trade and it wasn't a whole lot less than I was asking outright. For me it was a no-brainer. The dealer marked it up $400 over the trade value and sold it in a week.
Also try local classified "thrift" papers that are noted mainly for selling used stuff. Around here, I like Hocomo Freddies and the Penny Saver. They're often given away at convenience stores and the like.