I'd be willing to bet more people knew how to process the wildlife they killed in 1930 than today. The urban centers are full of people, many more than what were making cities thier home, back then. Yes, the outskirts of every large city will be desolate, in terms of wildlife, soon after ShasHTF. I doubt most people will make it 30 miles from where they were when the big bang happens. Draw a circle 30 miles from the suburban city limits, all around the metro; you don't want to be there. Outside of that circle, make 50 mile circles around medium sized cities, say populations under 100K; you don't want to be there. Cities with populations less than 20K people get 100 mile circles. This area isn't as bad as the others unless it touches (especially bad if it overlaps) a circle from a large city. Towns of less than 2,500 don't get a circle, but do get included in any other circle they are tied into. Now, how many people are included outside any circles? Not many. How much land in the continental United States is included? My guess is tens of thousands of square miles.