The message of "The Same River Twice" is you're only young once, so you better enjoy it. Watching the five main characters when they're young in 1978 on a nudist rafting trip in the Grand Canyon, and then picking up on where they're at 20 plus years later, is alternately sad and fascinating. The two women, Danny and Cathy, are just amazingly beautiful when they are young, I could watch Danny walk around in the nude all day! Danny keeps her youthful physique into her late 40s when we see her later, whereas time seems to be a little rougher on Cathy. All 5 characters, Danny, Jeff, Cathy, Barry, and Jim, seem to lead rather pleasant lives as they enter their 50s. But their youth is gone, and it's kind of sad. This is the kind of documentary you'd only watch once (it's no "Crumb"), but once is enough.