Re:Trip to Cincinnati area (Covington Ky.) in late July for Reds vs. Braves
I can't help you with Cincy itself, but there are some good stops on the first half of your drive. One that comes to mind is Bradley's BBQ in Sweetwater TN (I-75 exit 60). It's a reasonably new place, and they don't serve stew, but I really liked their chopped pork.
Just north of Chattanooga, in Ooltewah (around mile marker 9 or so), there's Couch's BBQ, which smokes uncured hams and serves the thin sliced pork on a toasted bun with lettuce, tomato and really hot, creamy yellow slaw.
In Knoxville, Triple-D favorite Pizza Palace is my wife's favorite pie, but I'm even more taken with their meat sauce and onion rings. I think I might prefer the pizza at downtown's Tomato Head even more. Either is a little bit of a detour from I-75. You could also get a steamed sandwich from Nixon's Deli or Gus's.