Richard Thomas directed about 5 or 6 episodes.
Richard directed:
The Song
The Fox
The Collision
The Great Motorcycle Race
John's Crossroad
Ellen Corby had two writing credits for:
The Separation Season 2 Ep. 3 Grandpa does a job for the Baldwin sisters in order to get money to have the electricity turned back on at the Walton house. He is gone all day and a tiff arises between him and grandma because he doesn't let her know what he was doing.
The Search Season 4 Ep. 15 Olivia, Jim Bob and Elizabeth are lost in the forest.
Michael Learned had one writing credit for:
The Legacy Season 7 Ep. 19 Miss Emily thinks that the handsome young officer Ashley Longworth Jr. is her beau of yesteryear, but Ashley only has eyes for Erin.
The acting credits for ALL shows/movies that the following appeared on are:
Will Geer (Grandpa) - 106. He surely would have had more but he was blacklisted during the McCarthy era for refusing to testify before the House committee on Un-American affairs. From 1951 to 1966 he only had 6 acting credits to his name.
Ellen Corby (Grandma) - 249
Ralph Waite (John Sr.) - 87
Joe Conley (Ike Godsey) - 56
Mary Jackson (Emily Baldwin) - 103
Helen Kleeb (Mamie Baldwin) - 130
Nora Marlowe (Flossie Brimmer) - 121
Robert Donner (Yancy Tucker) - 133
John Ritter (Rev. Matthew Fordwick) - 130 He would have had more but he died suddenly at 54 years old.
Peggy Rea (Rose Burton) - 95
John Crawford (Sheriff Ep Bridges) - 214
Beulah Bondi (Martha Corrine) - 86
As of right now the following have:
Earl Hamner Jr. - 1 The Journey Season 2 Ep. 1 (Michael MacKenzie). He has 42 credits as a writer and 13 as a producer. He will be 91 on July 10th, 2014.
Michael Learned (Olivia) - 61
Richard Thomas (John Boy) - 105
Jon Walmsley (Jason) - 26
Judy Norton (Mary Ellen) - 35
Mary McDonough (Erin) - 44
Eric Scott (Ben) - 18
David Harper (Jim Bob) - 13
Kami Cotler (Elizabeth) - 11
Ronnie Claire Edwards (Corabeth) - 38
Robert Wightman (2nd John Boy) - 15
Tom Bower (Curt Willard) - 156
Lynn Hamilton (Verdie) - 63
Hal Williams (Harley) - 66
Mariclare Costello (Rosemary Hunter Fordwick) - 53
Tony Becker (Drew) - 48
Leslie Winston (Cindy) - 12
Morgan Woodward (Boone Walton) - 126 He will be 89 on September 16th, 2014.
Richard Hatch (Wade Walton) - 87
William Schallert (Stanley Perkins) - 366 He will be 92 on July 6th, 2014.
One interesting thing I found out:
Will Geer was on the TV show "Hee Haw" as himself (Season 8 Ep.1 - 1976). I grew up watching that show and I don't recall seeing him on it. I would love to see it.