Something like this:
He'd need 59% in OKC & Comanche, 57% in Cleveland, 53% in Muskogee, 52% in Tulsa, 42% in Wagoner and Pottawatomie, and 41% in Canadian and Rogers. A lot of smaller counties in Little Dixie and its periphery come down to sheer coin flips here.
He'd need 25-30 point swings in the most populated counties; there'd be no improvement in the Panhandle and the most western portions of the state; from there, the swings would grow in strength as you move east until you reach the most Democratic-friendly portions of Little Dixie, where swings in his favor would exist, but would be tapered compared to some other regions.
Yeah, you pretty much hit the nail on the head with this one. A Democratic victory in the style of 2002 is pretty much impossible here now. It's a tall order, but I think Edmondson will be able to play well in OKC and surrounding areas considering Cornett lost. Tulsa I'm more worried about since Stitt has the home advantage but I don't think it's impossible for Edmondson to win it, a lot of the massive swings we've seen in special elections here have come from districts around Tulsa.