In "The Conflict" from season three, it's established that Martha Corinne was forced to give up her home due to the construction of the Blue Ridge Parkway. In this episode, when John-Boy takes her back to see her old home site, there is no highway to be seen.
At around 34:35, just as Beulah Bondi starts to walk away, Richard Thomas looks at someone off camera, smiles and winks.