Interesting that this will be my first post to this forum when it's a case that is long cold and probably rarely remembered, but I just got back from a vacation in the Smokies, and have thoughts.
I was reading about Trenny Gibson's disappearance the night before I walked the same trail to Andrew's Bald, so it was uppermost in my mind as I walked. She disappeared from the trail on a school trip and it was thought she either fell, wandered off or was abducted.
The abduction scenario is now on the bottom of my list after visiting the trial. It's a trail that begins and ends in the parking lot to Clingman's Dome, which is an extremely busy area. Now, I try to never dismiss an idea or get fixated on only one, as that leads to tunnel vision and makes me no use to any mystery. So an abduction COULD have happened, but I feel like it would have had to have happened in the parking lot, not on the trail, and it would have had to have been an impulsive snatch. After all, killers take vacations too. Trenny seemed a bit of a handful to raise, and very friendly. If a guy realized he could get her in his car easily, he might have gone for it. But having her schoolmates and teachers all around, and the fact that he would have then had to drive down miles of mountain roads at low speed makes that seem... really risky.
Being abducted from the trail itself seems impossible. The trail runs along the side of a steep mountain. If you step off the trail at all you are either immediately climbing steeply up, or you're sliding downwards. There are no even parts (except very close to the bald, but then it quickly gets steep again) and bushwacking off trail is very, very difficult. More so, I would imagine, if you're trying to drag a teenager along with you.
My gut feeling is that, because of the steepness of the trail, she somehow stepped off for some reason and then couldn't get back on. If she needed to go to the bathroom, or she wanted to smoke something, whatever. Your choice would be to go up or down, and statistics show most people go down. The problem is, once you start down, it's so steep that you could easily slip and just keep sliding. OR, even if you don't slide, once you get far enough off the trail, trying to get back up the slope TO the trail would be horrific. You would literally have to crawl up the slope, grabbing the trees with your hands to help lift you up. If you don't have much upper body strength, you'd very, very quickly get tired.
You could also easily slide down to the drainage at the bottom without hurting yourself too severely. Sound doesn't carry far there either. We couldn't hear other hikers on the trail until they were almost upon us. It just gets swallowed by the trees and the immensity of the area.
Once you're down in the drainage it would be difficult to impossible to climb back up again. And you'd be easily disoriented. The only thing you can see is the top of the trees above you. You cannot see any distance at all. You can't even see nearby hills. And the hills are endless. Once you started up the wrong slope toward open wilderness, you'd be done for.
I honestly think she deliberately stepped off the trail, slid down, got disoriented and walked away. Then she probably did what all the others before have done. She curled up in some little place to stay warm and died of exposure.
But who knows? It was such an intriguing mystery to think about as I hiked. I kept scanning the trail as if I might find signs of her, despite that fact that decades have passed since she disappeared. My mother and I both occasionally asked: "Where are you, Trenny?" while we hiked. It was sort of bittersweet.
