Texas Detour. A group of fancy teenagers in a 1970's van breaks down or gets stolen in a hick Texas tow. Stars Cameron Mitchell, the familiar face of 1970's actor Mitch Vogel, Veteran Western actor R.G. Armstrong and a naked (at one point in the movie) Priscilla Barnes (Three's Company) Hickspolitation everywhere.
http://www.imdb.com/title/tt0078379/?ref_=fn_al_tt_1