This house set on the RKO Lot in Culver City was rebuilt on The Warner Bros. lot when Mayberry RFD moved to The Burbank Studios for their third season in 1970. It was cancelled a year later, and The Waltons moved in shortly after.
(Third season WB backlot below)
Mayberry RFD 1968-1971
The Waltons 1972
The third version of this set was built on The Warner Bros. Ranch after a fire destroyed the WB original. It was built for a Waltons Reunion TV Movie, and then in 2002 it was used on The Gilmore Girls, where it was renovated as The Dragonfly Inn.
Check out the lack of subtlety of this very conspicuous telephone placement. Sitting over Carol‘s shoulder, you knew a call was going to be made, just waiting for her to turn and pick it up.