I also saw it when it came out (ironically, at our drive-in). Piper Laurie just came out of her Oscar-nominated role of Margaret White in Carrie. It seemed that she was destined to become a come-back middle-aged actress appearing in horror films ala Bette Davis and Joan Crawford. Fortunately, that didn't happen, especially since Ruby was not that, shall we say, "memorable." The plot was all over the place and the acting over-the-top. The direction was completely mis-directed. I also don't remember much of it and like MB I have no recollection of Roger Davis in it.
Gerard