When you talk to your broker, make sure to see if your state is one with a Recreational Use Statute in place. (Complements of the RAF.)
What it does is treat anyone who balls up their plane on your field, even if they are invited as a "trespasser". So, if they try to sue you, they have no standing. This works the same way as a hiker or fisherman.
This works as long as you are not trying profit from the runway and there is no known dangerous conditions on the runway. (Ditch, cable, equipment parked in the runway, etc.)
Here's the map.
We had one member who's liability insurance was reduced when he showed this to his broker.
Good luck!