Bookmark this website   
http://www.dnr.state.oh.us/parks/overnightfacilities/camping/ohiocamping/tabid/497/Default.aspx   
Salt Fork was the last place I went.  It is the largest state park in Ohio if I remember correctly? It had electrical hookups and showers in the "primitive" campgrounds part.  Driving around Salt Fork is nice and scenic with a few hills.  The grounds has a nice lodge, a golf course, many many trails to walk, also a marina where you can rent boats.  There is a hunting area as well if you get into that.