In November 1904, to broaden his architectural experiences, Willson started an extended tour of Europe, including France, Germany, Italy and the United Kingdom.
In late 1906, took charge of the offices of architects Link & Haire in Butte, Montana, where he worked until returning to Bozeman in 1910.
[2] Fred Willson played a significant role in the architectural face of downtown Bozeman and surrounding residential areas.
His European experience significantly influences his designs which include representatives of multiple architectural styles—Georgian, Mission Revival, Art Deco and Craftsman.
Willson donated his expertise in order to promote the National Park Service rustic architectural style.
Many of his buildings are landmarks in downtown Bozeman—the Gallatin County Court House, the Baxter Hotel, the Hamill and Blackmore Apartments.
In a 1954 address at Montana State University, Willson expressed his architectural philosophy: Since no two problems are the same, the architect must visit the site, become intimately acquainted with the family or owner who is to occupy the structure.
Few people realize the care and thought necessary to secure the maximum of useable (sic) space and still have an attractive interior and exterior.