Blackberries are HERE! I've never seen them as large, plump and sweet*. With last night's rain and more expected tonight, the coming week will likely be optimal for picking (7/24 - 7/31). If you wear long pants, venture off the wide main center grass path or into portions of the old peach orchard. Otherwise, there is presently great picking along the edges of the narrow cross path or along the grass path by the Beech Forest trail entrance.
Here is a recipe for a Wild Blackberry Buckle http://thefreerangelife.com/wild-berry-buckle/ (it even includes a few Wineberries which can be found in CRW but I think they have already come and gone along with the wild raspberries).
* Wild Blackberries can be a bit seedy, so favoring the darkest berries with plumpest drupelets will yield the sweetest fruit and be well worth a few seeds stuck in the teeth!