Driving east across the big O after a late movie? Extend the fantasy and take the road less traveled: The wee hours are the best time to experience the time-capsule that is MacArthur. Its heyday ended long ago via vivisection by I-580, this once-thriving strip seems frozen in amber, a wash of mercury-vapor lighting turning everything monochromatic and grainy. Pop in some mood music, and if you have a classic set of wheels, all the better. Start at the Radio Doctor (MacArthur and 14th St.), a tiny storefront with Deco detailing resembling a Bakelite-surfaced radio from the ’30s. Around the bend looms the Altenheim, the German old folks’ home, evoking a grim, end-of-the-line sanitarium. Ride the sinuous S curve down to the Dimond district as you imagine squealing tires and a Packard in hot pursuit. Catch a glimpse of the glowing Mormon Temple, perched on the hillside like something from the set of Lost Horizon. Fast-food joints from a slower era pass by: Kasper’s Hot Dogs, Loard’s Ice Cream, Donut Corner, Giant Burgers. Great neon beckons from old motels. Cue Norman Bates: “Oh, we have twelve vacancies. Twelve cabins — twelve vacancies. They, uh — they moved away the highway.” To paraphrase General MacArthur himself: Old boulevards never die, they just fade away.