Historically the park existed but now it's covered with trees. You can make out the old parking lot and road, etc when you walk around there. You can park off of the HW 380 assuming there is a free spot in the entrance area that is blocked off. However you would need to drag or cart your yak 100' yards or so to get to the water and there isn't any sort of formal ramp. I wish they would open the parking up there at the State Park and simply block off the trails if they are not safe!
The Corp is dumping 1400 CFS of water out of Ray Roberts right now which requires some care. I hit the 428 launch spot a few days ago for the first time when they were letting out 700 cfs and even then some fellow kayakers ran into trouble due to the current.
Scroll down to see the CFS. http://www.swf-wc.usace.army.mil/rayroberts/
The 428 spot holds a fair amount of small black bass but it lacks as many deep holes and lazy bends that are easy to find further down stream.