Allen built a scale model of the house to aid in planning, in addition to models of the layout he planned to build. His planning was very thorough. Early plans included the use of real water in scale rivers and lakes. Construction began in January 1954. One feature of the layout was Devil's Gulch, a part of the basement not excavated, but shaped, with concrete poured over it. Allen constructed the layout almost completely by himself. He devoted the next 20 years to this project.