The Garth Years include:
Even before the U. S. Government accepted title to the monument property in 1940, National Park Service representatives were planning its development. As early as 1939, engineering surveys and historical studies were under preparation for the monument's master plan. An archeological investigation was an important early step in this plan so Thomas R. Garth, a historical archeologist, was hired in December 1940 and entered on duty January 7, 1941.
Since the Whitman National Monument was coordinated with Mount Rainier National Park, Tom Garth was supervised by Maj. Owen A. Tomlinson, who was both superintendent of Mount Rainier National Park and coordinating superintendent of Whitman National Monument. Tomlinson, in turn, reported to the Region IV office, then located in San Francisco. After July 1941, Major Tomlinson was promoted to the regional director's position and John C. Preston became the new superintendent of Mount Rainier and coordinating superintendent of the monument. This was the basic administrative structure until Tom Garth transferred to the Smithsonian Institution in 1950.
Good communication existed between the three areas. Most decisions concerning the monument were made by regional personnel in consultation with the coordinating superintendent and Garth. On matters concerning future development and the master plan, regional personnel such as Olaf T. Hagen, Regional Supervisor of Historic Sites, and Landscape Architect C. E. Drysdale conducted on-site investigations. However, when it came to the actual excavating, according to Garth, "They left me pretty much on my own." 
Generally Garth was alone at the mission grounds except when temporary laborers helped excavate or when Marvin M. Richardson or Elmer R. Alexander, local historians and avid monument supporters, guided tours on weekends. Although Garth was employed primarily as an archeologist and only "incidentally as a custodian,"  as the only employee on the site, he was required to do odd jobs out of necessity. When not excavating, Garth maintained the lawn around the Great Grave, checked the Monument Shaft for vandalism, and guided tours and gave lectures to visitors. In fact, visitors absorbed much of his time: "[High visitation was] maybe one of the problems. I'd get started digging and would have to stop and try to conduct the visitors around." 
Though varied duties were sometimes a problem for Custodian Garth, the park was not sufficiently developed nor large enough to warrant another full-time employee. In fact, almost as soon as excavations began, the Whitman National Monument essentially closed from 1942-1946 due to World War II. Garth transferred to the Permanente Metals Corporation while neighbor Ray Shelden was employed as the mission's temporary caretaker. Even after park operations resumed in September 1946, funds were scarce, even for the excavations. Thus, limited staff had to suffice. In spite of the mission's primitive stage of development from 1941-1950, due to the management skill of the regional staff and the archeological skill of Tom Garth, satisfactory progress occurred.
1941-1950 At first glance the excavations appear to be the only issue that demanded management's time from 1941-1950. Although completion of the archeological work was the main accomplishment of the 1940s, several important decisions concerning the park's future were made at this time. The issues included the archeological and historical research, the Work Projects Administration, grounds development, and finally the adobe workshop/museum. An examination of each follows.