Almost all park museums used a narrative approach, with exhibits sequentially arranged to present a series of related ideas illustrated by carefully chosen objects and graphic supplements.68 Both laboratories tried to place every object and label within the best viewing range, a quite limited vertical span. Both used dust-tight cases with external lighting to protect vulnerable specimens on exhibition. Current taste called for recessing most of these cases into furred walls, which gave a neatly finished appearance of permanence without hindering future flexibility. Exhibits not requiring encasement usually took the form of open panels attached to the walls. The need to ship exhibits from the laboratories to the parks favored units of moderate size. So did local maintenance considerations. The latter also dictated general uniformity in exhibit lighting provisions. Under budgetary constraints exhibit rooms allowed floor space for the number of exhibits proposed and the visitor load anticipated but not for designers' flights of fancy in exhibit layout. Considerations of durability and maintenance led both laboratories to use similar structural materials. They shared information on their experience with various plywoods, hardboards, plastics, and paints as well as with silk screening and photo mounting. Their principal point of disagreement involved circulation theory.

Sequential exhibits depend for maximum effectiveness on people viewing them in a particular order. The relatively few museums outside the parks that stressed sequence generally either structured or obtrusively marked a one-way path for viewers to take. Disliking regimentation and obvious route marking, both laboratories aimed to make the sequence as easy as possible to follow without restricting freedom of movement. From published studies of visitor behavior, confirmed by personal observation, they knew that most people tend to turn right when entering an exhibit room and proceed in a counterclockwise direction, pausing at exhibits that catch their interest, glancing at others without stopping, and usually leaving the room by the first exit encountered. Of course, exhibits especially attractive because of size, motion, sound, or some other factor might divert individuals from the normal route.

Park museum planners worked with such behavior patterns in mind. They usually asked the architects for a single undivided room with a wide doorway through which visitors would enter and exit. The eastern laboratory consistently aimed to have people move around the room in a generally counterclockwise direction.69 John Jenkins, on the other hand, felt more comfortable using a clockwise path when the architecture made that a simpler solution. Both laboratories succeeded in getting most people to follow the intended sequence up to a point. Circulation difficulties arose when the next exhibit in the story line was not the next one along the righthand wall. Space limitations ordinarily required exhibits to occupy the center of the room as well as the perimeter, which necessitated "bouncing" viewers back and forth across the aisle between peripheral and central units. This practice, accomplished to some extent by various extensions of the furred walls coupled with visual attractants, tended to make the sequence too complicated. Associate Director Eivind T. Scoyen recommended numbering the exhibits, but the Museum Branch feared the numbers would distract attention from the interpretive content.

The recurrent problem of circulation underlined a longstanding need the branch felt for critical evaluation of the effectiveness of park museum exhibits. The specialists who designed and built the exhibits had little or no opportunity to observe how they worked. A small installation crew got a brief look at the finished job, usually through tired eyes, just before the formal opening. Almost never did planners, preparators, or their supervisors have an adequate chance to see the museum in normal operation, to watch visitors react to the exhibits, to learn which features seemed to work and which did not.