It's an interesting way to see this part of the world. A lot of the businesses along these former arteries are roadside attractions frozen in time: motels for travelers, big old-style theme restaurants, etc. The streets mostly run along railroad tracks and there are lots of bars, industrial plants, and other working-class businesses.
It's a lot like hitting a small town in some other part of America. Less malls, more "Jolly Jack's Cocktails, Games, and Girls" and "Hazy 8 Motel".
People from other parts of the wolrd assume that Southern California is a set of malls connected by freeways. I think the rest of the real estate is now inhabited by the Morlocks they forgot, who work and drink and crawl about under the freeways, missed by the luxury cars roaring overhead from pavilion to pavilion.