First Step for Permits

I'll be filming a short film in late August and I've found a few locations that I need to try and lock down. The big one is an outdoor setting which takes place on a public road in a rural town. Along this road are maybe three or four houses and shutting down the road for a day would actually be very simple as it is not a high traffic area (it's a back road). My question is, do I approach the land owners first, seeing if they'd be willing to have me film along the road and on their property (about only 50 feet off the road) or do I approach the township first to get permission to film on the public road? Any ideas would be greatly appreciated.