Mainly fireroads. There are a few variations on the loop. The most common is the race course that starts next to the dam. IT is approximately 12 miles long with several relatively steep climbs with corresponding down hills. The course is not technical, but is pretty tough.
How to get there:
From 81, take 181 to Kingsport. Follow the Bays Mt. Park signs to the entrance.
There is a $3 gate fee (per car) and I believe a 1 time fee of $2 to register your bike.