From Dr. Mathew Gerard:
This route adds the trail looping around the ‘top end’ of the lake. It is unpaved, with tree roots, rocks, and narrow sections to make it a little more technical. Parking is at either end of the bridge crossing the lake, the lots are often full at peak visiting hours. Route can be navigated either direction, the hills are strenuous regardless!
(Bonus: It’s not uncommon to see Blue Herons and other wildlife at Lake Johnson!)
Link: Lake Johnson 4.5 miler