Last one for tonight. I think these three go together, though I don't have any suggestion as to who the two women might be. The background looks very much like a place I visited in Wyoming years ago, but I can't find a picture of it anywhere.
There are a couple of women missing from that area in the right time frame. Carlene Brown and Christy Gross, both 19 at the time, went missing from a rodeo in Rawlins in 1974. Christy's body was found a few miles away almost 10 years later; Carlene has never been found. I couldn't find a picture of Christy anywhere, but I'm attaching Carlene.