We made several phone inquiries and then finally visited May 15-17 weekend. Met a ranger at the closed gate to Jones and he explained that they are inexplicably remaining closed THROUGH Memorial Day weekend. This is the opposite of the recorded message, so save yourself the disappointment.
Open are Steamboat State Park and Soap Lake State Parks. Also, a park north of Coulee City is open as is the resoerts at southern end of Banks Lake.
There is little to no cell service in and near Jones Bay, but there is some at the State Park south of it.