That's interesting. Melody also said they wanted her to play Ben's wife on the Waltons, but signed with Y&R. Melody had also appeared in an episode of Eight Is Enough. All three were Lorimar shows. Terry Lester also appeared in several of the Lorimar shows at this time (Dallas, Eight, etc...
David Jacobs said he wanted Stepfanie Kramer as Lucy, but the higher ups decided she should be a nifty blonde. He cast Kramer on his short lived series Marriage The First Year instead. Leigh J. McCloskey (Mitch) and Constance McCashin (Laura) also appeared on that series.
At one time there was a huge photo online of the casts of The Waltons, Dallas, Eight Is Enough, and Marriage The First year circa 1979 all gathered together, but it has since vanished.