If you're in Tahlequah, you absolutely must try Del Rancho for the BEST chicken fried steak you'll ever have. I like the steak sandwich, my honey likes the dinner. Either way, it's something you'll never forget.
In Cookson, there is a BBQ joint - not sure of the name but I've heard it's good.
I doubt there's many chains around there so you'll have to pick and choose, but most definitely try Del Rancho for a sure thing.