She played three different girlfriends
Mimsy Farmer and Paul Petersen
Mimsy Farmer (Born February 28, 1945).
Mimsy Farmer (born Merle Farmer) is an American actress, artist, and sculptor. She played in Spencer's Mountain (1963) and More (1969). After a brief film career in the United States, mostly portraying party-girl types, she moved to Italy. Most of her career has been spent in Europe.
Farmer guest-stars on The Donna Reed Show in three different episodes, each time playing a different one of Jeff's love interests. She appears in "The Swingin' Set" (Season 4, Episode 35), "The Father Image" (Season 4, Episode38), and "Boys and Girls" (Season 5, Episode 30).