Hmm. Well, making a wilderness area more scary (removing some small towns, etc) is probably less disruptive than picking a small city and making it bigger to satisfy the other requirements. I suspect you're going to have to do a bit of that.

After all, some of that wilderness around the Twin Cities lacks nom-nom because it's been tamed. If it had been hosting Red Talons since the mid-1700s, people would have left it alone more, and it would have stayed scary :)