Stone Mountain is a great place to go hiking, just an hour from the Triad on the eastern edge of the Blue Ridge Mountains. The most popular trail is Stone Mountain Loop Trail, a 4.5-mile loop that includes several of the park's main attractions. There is an upper and lower trailhead parking areas on either side of the loop, but I'll describe the trail coming from the upper parking lot near the Visitor Center. Past the bathrooms, the trail leads up to an old chimney and a split in the trail. Go right towards Stone Mountain and begin climbing up. There are a couple of granite outcrops that have good views of Stone Mountain from the side and then some switchbacks to get up to the summit. Be careful and don't walk off the trail on the granite outcrops. They get steadily steeper and its possible to get stuck and not be able to get back up. Heading down the mountain, eventually you'll come across the lower parking lot. Past here Wolf Rock Trail splits off - take this to add another 1.5 miles and see Wolf Rock another big outcrop facing west with views of the Blue Ridge Escarpment. Continuing on, Cedar Rock Trail will split off - this adds maybe less than a mile and has perhaps the best views of Stone Mountain. The Cedar Rock Trail ends back at the Stone Mountain Loop Trail. Go left/straight to see Hutchinson Homestead or go right to continue on the trail. After a mile or two, a trail to Middle & Lower Falls. It's a mile each way so this will add about 2 miles onto the hike and there are a few stream crossings without bridges that will require rock-hopping. Finishing up the main trail goes past Stone Mountain Falls and up 340 (or so I've heard) stairs to the top of the falls. Use caution and don't cross the fence - a fall off a 200' waterfall would be fatal. The top of the falls leads back to the chimney and the trail back to the parking lot. Following all the extra trails, the total distance is about 8.5 miles for the loop.
The other trail for hiking in the park is Widow's Creek/Mountains-to-Sea Trail. The parking lot is on the other side of the park past the lower trailhead parking for the Stone Mountain Loop. Widow's Creek Falls is right next to the trailhead and definitely worth a stop. Widow's Creek Trail runs parallel to the creek for about 2 miles or so to backcountry campsites, after which the Mountains-to-Sea Trail splits off and heads up. For a mile or so, the trail is extremely steep and then levels off a bit, heading through a rhododendron forest before at Devil's Garden Overlook on the Blue Ridge Parkway. A hike up and back along the MST is about 12 miles round-trip.
There are four names waterfalls in Stone Mountain and State Park and all are within a couple miles of a parking area. Start from the upper trailhead parking near the visitor center and go towards Stone Mountain. After passing a chimney, turn left at the fork heading towards Stone Mountain Falls. Shortly, you will be at the top of the falls. Use caution and do not cross the fence. The waterfall is around 200 feet and a fall would almost certainly be fatal. To get to the bottom, head down the stairs (and remember, you'll have to go back up!). There is a viewing platform in the middle, and you can go out to the base of the falls at the bottom. Again, use caution on the rocks and don't go in the falls basin. Following the trail past the falls, another trail will branch off to the right leading to Middle and Lower Falls. Middle Falls is just a short distance down the trail, with a spur leading to the right. In the warmer months, some people slide down this waterfall into the basin. Waterfall-sliding is dangerous, but if you choose to do it, make sure to check the pool for rocks or logs or anything else that could hurt someone landing on it. Back to the main trail, follow it to the end for Lower Falls. The pool below the falls is nice to cool off on a hot day, but it's usually to shallow to slide off the falls. That's all the falls here. Backtrack to the car and continue on the road around the park. After passing the lower trailhead parking and a bridge over Widow's Creek, there is a small parking area on the right for Widow's Creek Falls. This is only a very short walk from the car and a very pretty waterfall.
There are maps and informative displays inside the visitor center. There are also local discussions and volunteer seminars to be involved with if interested. I liked the bear and butterfly displays especially.