I did the Stone Mountain Loop with a side trip to the lower/middle falls, for a total of about 6.5 miles.
The park is very easy to get to. Once you arrive, the facilities are pretty nice. There's plenty of parking and a large picnic area.
The trail was wide, well-maintained and clearly marked. I never felt in danger of getting lost, even though it was my first time here.
I did the Loop counterclockwise. The benefit of this approach is that it lets you save the falls for dessert.
It's 1.4 miles from the stone chimney at the start of the Loop to the summit if you attack it in this direction, and you spend most of it zigzagging upwards.
Once you get near the summit, the views over the mountain are spectacular.
A word of caution - it's basically a great big exposed dome and I would be very careful about being stuck up here in the rain or ice because it would get unbelievably slick.
Once you come down off the mountain - that long, amazing staircase and then the steps hewed into the side of the mountain - there's a long stretch of relatively easy hiking as you head around the loop to the southeast. I found this very calming and relaxing. I flew through this part. Take a couple of minutes to check out the old homestead and take in the view of the mountain's south face.
The lower/middle falls are worth the mile-long side trip.
The second big attraction is the big falls... 200', there are several observation points on the stairs. Be careful hopping rocks over the creek at the base of the falls.
Finally, big stairs back up to the top of the trailhead... a final little workout.
Parts of this hike were really beautiful, and it's close enough to me that I'll definitely be going back for another look, as well as to explore some of the side trails that I missed.
Bring plenty of extra water because this is a thirsty hike. Be sure to bring a pole or a staff if you have one.