The bad couch is gone! Nice mover guys came and took it away this afternoon. As they took it out I realized that the couch I wanted would never have fit into my living room. Ameer Radwan at Couch neglected to mention that the frame he ordered flares out at the back--a lot! At least 9" from seat to upper back! A straight backed couch, like the one I had, would have fit fine.
So now I'm going to experiment. I shall take my upholstered chair, masking tape a large piece of cardboard to the back to replicate the desired height, and see whether it fits through my truncated hallway. I love doing this kind of thing. Before I moved in here I measured everything, graphed it out to scale, used scale furniture models from a previous move, and decided on furniture placement. Worked out great!