Frances McDormand blended into the nomadic community so well that a local Target store offered her an application for a job. Her experience of living in a van took four to five months, covering seven states. She adopted a lifestyle of being constantly on the move to make the movie seem more authentic, rather than just acting the scenes.
With the exception of Frances McDormand and David Strathairn, most of the cast members playing nomads in the film are actual nomads and local people, listing their real first names for their characters.
Frances McDormand nicknamed the van used in the film "Vanguard," which she decorated with her own personal items and slept in during the shoot. Eventually she stopped doing so because "it's much better for me to pretend to be exhausted than to actually be exhausted," she told The Hollywood Reporter.
Many of Frances McDormand's co-stars, such as Charlene Swankie and Bob Wells, had no idea she's a Hollywood star. Bob still did not know this until they shot an emotional scene in which Fern remembers her late husband, Bo. Afterward, he said to McDormand privately that it meant a lot for her to tell him that story and that everything was going to be OK. She subsequently revealed to him that her husband's name was actually Joel Coen and he was still alive, which surprised Bob as he learned that McDormand was in fact an actress.
The movie was filmed in seven states over the course of four months, during which Frances McDormand actually performed several of the jobs done by people who do nomadic work and inspired the book, such as harvesting beets and packaging Amazon orders with the CamperForce program.