Ongs Hat is a pretty small area. It would be hard to miss anything there. If you take a look on Terraserver you can see that the whole area is fairly dense woods with one road leading out to where the diner is.
Generally when there has been human habitation in the area, the woods take several hundred years to recover, and you can tell where things would have been. Even if there are no ruins there are things like odd clearings, non native trees, etc. There was none of that at Ongs Hat.
When Beck was there he mentioned a clearing with bits of bricks and a tumble down shed. That would have had to have been located right where the diner and the houses are.
Generally when there has been human habitation in the area, the woods take several hundred years to recover, and you can tell where things would have been. Even if there are no ruins there are things like odd clearings, non native trees, etc. There was none of that at Ongs Hat.
When Beck was there he mentioned a clearing with bits of bricks and a tumble down shed. That would have had to have been located right where the diner and the houses are.