In the early episodes, the background/incidental music is very familiar, and must have been used on another series.
It's not that I'm remembering what I heard 35 years ago when it was in reruns in the mid-70s. This has to be something that I watched in the past few years, even if it was an old series.
The shows I am coming up with as possibilities are:
The Brady Bunch
The Partridge Family
I Dream of Jeannie
Little House on the Prairie
At first I thought it might be from Bonanza, but that just doesn't seem likely.
Does anyone know?