If you want to understand the work of Lee Jones, "Invasion of the Girl Snatchers" is widely considered the best place to start your studies. Jones, with a little help from his friend Don Davison, also brought us "Shanty Town Honeymoon," "Moonshiner's Woman," and "Supervan."
Incidentally, some of Jones' alternate titles are quite worthy of Drive-In Academy Awards, such as "Hillbilly Hookers," "Little Whorehouse On The Prairie," et al.
"Invasion" was made around the same time as William Girdler's "Three on a Meathook." In fact, "Invasion" borrows some of the "Meathook's" sets and locations. Many members of the Louisville-based crew on "Invasion" were Girdler alumni, including Hugh Smith and Bub Asman.
"Invasion of the Girl Snatchers" hasn't been available on video since the late 80's, which is a crime. Keep your fingers crossed for a re-release sometime in the future!