By Crosby Doe Okay, let me admit this up front: I am one of the lucky ones. Not only do I sell historic and architect-designed properties for a living—which I love and have been doing in Los Angeles for over 40 years—but for 35 of those years, I have been living with my wife in a two-story hilltop manse designed by architect Joseph Blick with spacious interiors that open to views of the surrounding...