That was a classic Sixties trope that lasted into the Seventies: buttoned-down, repressed guy meets liberated free-spirited chick - the so-called "manic pixie dream girl" - who turns his life upside-down. You could give it a generation gap spin, and even reverse the genders and the ages (
Cactus Flower,
Harold and Maude).
More daring and gutsy: putting Roger C. Carmel in what you hope will be a major motion picture.
I remember Kay Lenz, IIRC she married David Cassidy.
She was also the girl in Rod Stewart’s “Infatuation” video.