My parents live on Turkey Creek [Ft. Loudon Lake]. The slalom course that used to be in Turkey creek was owned and maintained by the UT Waterski club. Unfortunately, the course and the ski club are both long gone (as far as I know). Wouldn't matter anyway as the boat traffic in there is terrible now. When my parents moved there one side of the creek property was farm. Now, it's a fully developed neighborhood.
There was a slalom course on Douglas lake, adjacent to the Mountain Harbor Inn among some islands, but as far as I know, it's gone too. (I haven't been on that lake in years.)
I have relatives also on both Cherokee and Watts Bar. The course we used to ski on Cherokee isn't there anymore. And I heard that there's a course on the upper end of Watts Bar, right near the town of Kingston. With Covid, I haven't been up there at all this season. These are the directions that I got: From the Kingston City park, head south, then bear to the left at the split and go under the bridge (up the Tenn river towards Tellico / Ft. Loudon). The course is in the 2nd cove on the right. Looking at the map that would mean that it would exist (potentially) in either Riley Creek, Chamberlin Branch, or Stamp Creek Valley. I had heard of a 2nd course on Watts Barr on the south end. A couple of seasons ago, my cousin and I went looking for it on a Sea Doo and came up empty. Might be worth investigating though still. I saw youtube videos of runs made in that course. Try searching youtube for course videos based on location and then see if you can engage the posters for info.
Sorry this isn't much help for what you're looking for.