Excellent 'urban wilderness' route in Knoxville! A little over one mile is paved asphalt. The balance of about 4.5 miles is single track in the woods. Some tight turns, rocks, roots, dirt/mud, and leaves. Fortunately for me it was mostly dry since I was wearing my racing road shoes (Nike VaporFly).
Note: my Garmin watch had some type of issue that I have never had before. The map shows a horseshoe-shaped route. However, I did run the complete Forks of the River looped course, starting and finishing at the parking lot off McClure Lane. The total distance and elevation gain are accurate based on the route GPX file. A little more than one mile of the map is missing. This portion of the segment is on paved asphalt. In the Splits part of my Strava link click on Mile 2 and forward, and you can see that part of the map highlighted. Click on Mile 1 and there are no highlights. This is the portion of the map that did not complete for some unknown reason. I was able to run this first mile much faster due to the clean asphalt surface and my racing road shoes.