The navmesh isn’t grid shaped, and probably wouldn’t provide useful information in this scenario. Instead, you could select a number of possible destinations (use a grid if you want) and run Navigator.GetPathTo() to determine if a valid path exists to each of your destinations. The pathfinding operation can potentially run for a while, so I would probably spread the calls out and do one destination per frame. You should limit the total number of pathfinding steps as well, depending on the overall size of your graph and the distances you are willing to allow. (100 is an ok default usually.)