Lauren beat me to my recommendation of Clark's. Great chicken! You can make reservations any day except Sunday. If you are going with kids, it is a 5-10 minute drive south of the Arboretum on Rt. 13. Our kids used to love to go there, especially in the fall, roll around in the leaves. The Japanese Garden is kind of neat. A good walk after Clark's makes you feel not so guilty about stuffing your face. It is also about 20-30 minutes from the Longaberger stuff off Rt. 16. The Natomah restaurant in downtown Newark is about 15-20 minutes off the highway right on the cental downtown square. The food is very good, reasonable and you get a discount (10-15%??) if you are a AAA member.
In Wheeling, there is Ernie's Steak House, which has been there forever and a red sauce Italian joint, Figarettis.
Clark's Dining Room near Hebron off route 70 is a local landmark - even the Sterns have written about it. Chicken is their specialty. Check it out at http://www.clarksdiningroom.com/
Also, Maria Adornetto restaurant in Zanesville is neat because it has been around since the 30's (I think) and has a great Rat-Pack decor. The food is very traditional red-sauce Italian, but it is worth a stop just for the sunken bar. Address: Maria Adornetto's Restaurant 953 Market Street, Zanesville, OH 43701, 740-453-0643. It's right off I-70.
re: Lauren in OH
I used to drive 70 at least a couple of times a year btwn DC and MO. Now it's rare with a super young kid. I'm interested in Clark's.
Zanesville, though, used to be a regular for me as I ended up making the trip in two days most often, and ended up sleeping around there. They at least used to have a plethora of good to great diners. The best, Mickey's, went downhill a bit from being stellar when one family passed it to another - it's a building that's been there since before 1900 and been a few things, but almost always served food. I think Mom's is another one, but yet there were about 2-3 others I had stopped in at one time or another.