I highly recommend Lake Ouachita State Park and surrounds. Fantastic scenery. Decent, if narrow, roads. Lots of twisting turns. Great for a nice cruise.
There are a lot of good roads to the West and Northwest of LR. Throw a dart near Fayetteville or Hot Springs and you'll find a nice road.
Edit: LOSP
is a state park so it's not for speeding around and playing racecar. Still a great cruise.