OH-78 is one of the best roads I have taken in southeastern Ohio. Many curves and elevation changes. Definitely demands your full attention, but is a very exciting road. I enjoy the section west of I-77 the most. There is a small roadside park, Miners Memorial Park, 16 miles west of I-77. Has a large bucket from what was once the world's largest dragline. Worth stopping for a few minutes to check it out.
Really good combination of twisties and good surface = FUN!