My ideas: 1) Post flyers on bulletin boards at local supermarkets, if they still have these boards in your area. Those aren't as likely to catch the impulse-driven crowd, but could drive business nonetheless. 2) Make a sign that reads: Garage sale....HONEY. Put it up and take it down as needed.
My opinion or, more like, what are possible pitfalls: If your township is truly not business-friendly, then they are not going to be supportive of a sign that remains posted by the road, even if the right of way is owned and maintained by the state. If they are actively business-unfriendly, then they may also take it upon themselves to determine if you are/are not a farm. In our state there is a difference between a property on which allowed agricultural pursuits are taking place, and a farm.
I hope this helps. Good luck on your sales! Keep us posted.