Glen and Randa (1971)
Glen and Randa is a 1971 rated X post-apocalypse movie directed by Jim McBride. It was co-written by McBride, Lorenzo Mans and Rudy Wurlitzer. McBride made the film for $480,000 with an obscure cast including Steven Curry, Shelley Plimpton, Woodrow Chambliss and Gary Goodrow.
More at Wikipedia.