Hillbillys in a Haunted House (1967)

 Hillbillys in a Haunted House (1967) 

Country singers on their way to Nashville have car trouble, forcing them 

to stop at an old haunted mansion. Soon they realize that the house is 

not only haunted, but is also the headquarters of a ring of international 

spies after a top secret formula for rocket fuel. (IMDB Jeremy Lunt)