Although the Moose fur trade museum proved exemplary from the standpoints of historical and curatorial scholarship, exhibit design, and execution, it severely stretched the Park Service concept of a museum's proper function in a park. Fur traders had crisscrossed the land within park boundaries, but specific sites of significant events or activities lay elsewhere. The exhibits could not direct visitors into the park to relate its prime features to what they had learned in the museum. This divergence from the site museum concept perhaps made it easier 14 years later to eclipse Grand Teton's natural history site museum at Colter Bay with a gallery of American Indian art, popular but also largely extraneous to an understanding of the park.

Management of the laboratory was especially difficult for a newcomer to the Park Service. The growing load of exhibit planning and preparation, combined with unfamiliar federal procurement and personnel policies, engendered innumerable problems. Production had just gotten into full swing in the summer of 1958 when John Jenkins was called back to Wisconsin for three weeks by a death in his family. This incident reinforced Jenkins' request for a second in command familiar with the procedures, policies, and standards the Museum Branch had found most satisfactory. As a result Floyd LaFayette moved from the eastern laboratory to become assistant chief of the western laboratory in January 1959. Although Jenkins and LaFayette would meet unforeseen difficulties, the move proved a happy choice for both men and a substantial benefit to the Service.

The first difficulty involved special assignments. When funding in 1960 enabled the long-delayed development of the Jefferson National Expansion Memorial to resume, Superintendent George B. Hartzog, Jr., demanded that the Museum Branch send him its best exhibit planner. Subsequent actions suggest that he would have preferred to leave exhibit designing to Eero Saarinen, the eminent architect who had won the competition for the memorial, but Director Wirth insisted that details of interpretation remain in Park Service hands.62 The Museum Branch accordingly asked Jenkins to undertake a six-month detail in St. Louis. Taking the content material being developed by a research team working at top speed under park historian William C. Everhart, Jenkins completed a museum layout plan incorporating more than two hundred exhibits under twelve thematic units. A new team employed at the park undertook detailed planning for the individual exhibits, but the project continued to make serious inroads on Jenkins' time.

The branch also drafted LaFayette to work on urgent problems outside the western laboratory's full program. In mid-1962 the American Museum of Immigration slated for the base of the Statue of Liberty critically needed help in exhibit planning. By no means a typical park museum in concept or development, it fell outside the team schedules, and the branch had concurred in letting the park historian and a contract curator undertake the job. Although both had done excellent work on park museum projects before World War II, the plan they produced revealed that they had not kept up with changes in the field: it analyzed and organized the immigration story skillfully but attempted to tell it with 1930s exhibitry. With time running out as structural work on the museum was about to begin, the branch asked LaFayette to prepare a new plan. He did so successfully in collaboration with the park historian, Thomas Pitkin, and Alan Kent. It took him most of the summer of 1962 with additional work on it interrupting his regular duties until its completion the following year.

The second difficulty that plagued the western laboratory involved staff health. After a series of unsuccessful operations during 1964, Jenkins died that September at the age of 53. His death deprived the Service of a true museum expert. LaFayette carried on as acting chief of the laboratory until appointed chief in June 1966. Then his health failed in turn. By that time the Service had largely accomplished its Mission 66 objectives and turned toward new emphases.