The Outlands is the phase boundary between the city and the Outer Planes. Its existences preserves the city's ambivalence, keeps it from being conquered by some conceptual force or another. Its desert is vast, but it is more its indifference that keeps strongly held ideas at bay. The Outlands and its few inhabitants are stubborn.
The highways that stretch from the city gates run through alkali saltpan, scrub plans, and stretches of sandstone buttes. There are a few settlements along the way: outposts and waystations run by those too noncomformist for city life or exiled for some other reason. There are also bands of evangelists and missionaries from other Planes working to convert travelers, though these will die out eventually, either in conflict or by loss of faith. Some of them get violent in their death throes, though. Most Everyone else is a traveler or trader, headed one direction or the other--or a bandit. Though the highways are most often lonely (that is their nature, not a description) many convoys and caravans pass along them, and they all ripe for the taking.
At the edge of the Outlands are the Border Towns. Their appearance vary from town to town, but they control the flow of traffic from whatever plane is on the other side. All are fortified borders, no matter how benign the appearance of the Plane on the other side, indeed the most benign are often the most dangerous.