Ok, I am going to show some ignorance here, but what is the Devils Triangle? I have lived in TN all my life and I have never heard of any area called that.
When I google it, it comes up close to Oliver Springs, TN near Frozen head state park. Is that where you are talking about? If so, Savage Gulf that @tgreco mentioned is farther south. And close to that is Rock Island, the Fiery Gizzard, Foster Falls, and a number of other places. UP closer to Oliver Springs you are close to the Blue hold natural area, Windrock park, Frozen head state park and also from there you aren't but an hour or so from the smokies and all the hiking you could stand.
Sorry for the dumb question, but we can probably put you into some pretty good spots, but I need to know I am pointing you in the right direction.
Thanks