Kaze no Na wa Amnesia, Kikou Souseiki Mospeada Recommendations
Both series involve a world in which society now follows far more basic rules of survival and in which many of the cities are rather broken down. In Mospeada, people can still talk, but similarities between the two are uncanny. Both also involve a group traveling around to different cities and have some similar experiences among them, even if their goals are different. If you want to see more ruined cities and people living in now terrible societies, check the other out.