This was a really good ride except for the fact that about one fourth - one half was on the main road. One side of the lake is all road and the other side is all trail. Everyone we met was super friendly.
So the loop is actually part trail, part road. However you can ride for a good 15 to 20 miles on the bike path if you plan for an out and back trip. The path has some great views and is a pretty smooth ride.