How do you structure the "large distance" grid?
Is it simply regarding not 100% passable areas as non passable? Or do you calculate a passability value for each "subgrid".
(you could make a short-distance pathfidning-testrun from each of the 4 sides "side-middle"points to each other 3 middle points to check if
there is a connection)
Or use a floodfill to see if each side is beeing touched...