Sarah Boll fastened portholes and gold decals to her living room walls and outfitted her bedroom with gilded panels, among other decorations.

Sarah Boll didn’t just rewatch Titanic. She rebuilt it—inside her New York City apartment. What started as a party theme spiraled into something closer to a museum installation, or maybe an obsession.

The decision to turn her apartment into an immersive theme experience for an audience of one (and her Italian greyhound, Vito ...