Cassie Poulson was a resident of New Springfield, for a few years, and the wife of Jeb Poulson.
She grew up in Miami West 4, when it was only a minor suburb of its parent city on Datum Earth.
In 2035, she, Jeb, and a party of people treked across the Long Earth to Earth West 1,217,756, where they founded New Springfield.[1]
The Long Utopia[]
One day, in July 2036, she decided to dig a cellar next to her house, which could be used as a refuge from bandits with Stepper boxes as well as tornadoes. She accidently discovered a cave, and glimpsed a silver beetle inside it. Yelling, she attracted the attention of Josephine Barrow, one of her neighbours.
Not wanting to have to leave the town she had spent the last year building, she didn't tell Josephine or anyone else about the encounter, or the possible threat it posed. So she covered the hole over with wood and then forest-floor dirt.[1]
By 2052, the Poulsons as well as the rest of the founders of New Springfield had left as the new generation didn't want to work in farms when they could just step into the neighboring worlds for food. They had abandoned their home, which was now known as the old Poulson house. It was being used as a swap house, by the current residents.[2]