Barkingham Park is my favorite Charlotte dog park, even though for me it's a bit of a drive. It's usually occupied by at least a few dogs, even at weird times like 2:30pm on a Wednesday... and on weekends with nice weather the place is absolutely full of dogs and people!
About half of the park is wooded, the other half is an open field. It used to be grass, then it was alternately dust bowl or mud bog - currently it's covered with sand and pea gravel, which seems like the best solution under the circumstances. When it's dry, it gets pretty dusty when a pack of racing pups pull up short right in front of you, but you can always hang back in the wooded area a little and still keep an aye on your furry friend. As far as the muddy times, it really doesn't get too bad - I've seen much worse at some of the other local dog parks.
There is a loop trail that goes around the wooded section, you can get in a nice walk with your dog off leash or just enjoy some exercise while your dog plays with new friends.
There's also a separate area for small dogs, although I've noticed that those dogs usually end up joining everybody else in the big park.
It's also a nice bonus that you can take your dog for a walk or run on the Reedy Creek trails before or after the visit to Barkingham Park!