Oh, check out the ButterBurger map. Why'd they skip over Oklahoma?

I'm kind of interested in Oklahoma and Texas right now, since I just read That Old Ace in the Hole by Annie Proulx, who also helpfully blazed the Wyoming trail in advance of my own little trip. Also in the name of Texas research, I'm re-reading Cormac McCarthy's All the Pretty Horses... well, really, I'm reading just for the pleasure of his incredible writing. Kept me up later last night than was really good for me.