This is a relatively easy 5 mile loop trail that follows the shore of Lake Fort Smith, then climbs and returns on the hillside above, offering some nice views.  The trail passes a small waterfall that only flows following rain/wet weather, old home sites (including a couple of rock chimneys) and past the Shepherd Spring itself.  The trail begins behind the Visitor Center.  You can also access the trail from the East end of the campground loop (which will be a shorter hike).