Fossett is an accomplished sailplane pilot
He probably figures that if he can get within a few hundred miles of Kansas, he can glide it in. I don't know what the lift to drag (L/D) ratio of the plane is with a dead engine, but it wouldn't surprise me if it's at least 30:1. From 45,000 feet, a 30:1 glide ratio could carry him about 270 miles in still air. Given a tail wind (or some thermals!), he could probably go further. Hell yes, he'll go for it!