I make the trip from Chicago to Cleveland several times every summer. There's a good reason you don't see a lot of discussion about "decent, non-chain restaurants" in Northern Indiana. It is because there are very few. You'll be way better off putting pedal-to-the-metal and choosing your dining options in Ohio.
You don't say what time you're leaving Chicago, so gauging where you'll be around lunch time/early dinner is tough. The whole trip isn't too much more than six hours, so if you leave Chicago at 6:00am, you could potentially be eating lunch in Cleveland proper by noon.
Just west of Cleveland, right on the shores of Lake Erie, is the
New Sandusky Fish Company. They've got tremendous fried fish, served as a dinner or sandwich, with a modest selection of sides. A couple of caveats:
1. All dining is outdoors, next to the main building. The local aquatic fowl have figured this out and become quite bold in their approach to diners. Avoid eye contact. Also, avoid dining near idiots.
On my last visit, I managed to distract the birds by flinging a few French fries far away from the picnic table area, sending them away from where I was. Minutes later a table full of mouth breathers sat down near me and started tossing food directly at my table, sending (literally) a gaggle of hungry, mean looking geese my way. Naturally, when they'd gobbled up all the scraps thrown by the morons, they started demanding tribute from me.
I got my revenge by eating up quickly, going to the trunk of my car, pulling out a baseball bat and beating them (the mouth breathers, not the geese) to death. Just kidding about that last part. Or am I...?
Anyway, simple solution; if the birds are out and about, eat in your car.
2. I don't recall them selling any booze, so BYO. I'm pretty sure there's a nearby liquor store where you can pick up some cold beers.
You didn't ask for any suggestions specific to Cleveland, but I can make plenty of recommendations in that area as well. Almost none of them involve angry waterfowl, or death by bludgeoning. Let me kow if I can help.
Have a great trip!
Buddy
New Sandusky Fish Company235 E. Shoreline Dr.
Sandusky, OH
(419) 621-8263