I would hesitate to tell someone not to trespass if they had footed part of the bill. Of 300 conserved farms in Vermont, about 100 have public access. I think so, if the acces is appropriately restricted and located, and it's carefully managed by a town or nonprofit. An example would be a pedestrian trail located off to the side of cropland. Community support can be useful, but neighbors can also be a problem.
Farms are big and sloppy, so they make an easy target.
It now involves much more public access to the farm and the farmer. There are both benefits and problems when a farm becomes more of a public place. Overuse is a problem for farms in suburban areas. They're being trampled to death, they need more parking. They would do it before anyway, and end up getting zapped by the electric fence.