A little "toy" of mine that I play with when I get into my "I want to move now" mode, Land and Farm is a great way to find just about any rural property you want. The advanced search allows you to narrow your search as much as the type of property; ie, organic farm, vegetable farm, horse farm, etc. You can look by proximity to zip code or leave it open to the whole country -- either way, there are thousands of properties on there. They even have auctions posted if you're interested.
And yes, I found my dream place . . .