Goin' South (1978)

Goin' South
Comedy, Western, Romance
Henry Moon is captured for a capital offense by a posse when his horse quits while trying to escape to Mexico. He finds that there is a post-Civil War law in the small town that any single or widowed woman can save him from the gallows by marrying him.
Starring
Jack Nicholson, Mary Steenburgen, Christopher Lloyd, John Belushi, Veronica Cartwright, Richard Bradford, Jeff Morris, Danny DeVito, Tracey Walter, Gerald H. Reynolds
Directed By
Jack Nicholson