These snapshots were made by Frances Trammell McCormick in July 1940. This early pavilion (above) was quite different from the two that followed. It was an open-air shelter and likely held a concession stand. [I have a download of another snapshot from the same era of a much more elaborate structure which was identified as being at Crystal Lake but I’m having trouble confirming it; it seems unlikely that there would have been two large pavilions at the site around the same time].
The edge of the pavilion is visible at the extreme left of this photograph, made from the lake. A small wooden structure, likely a diving platform, is also visible. I believe there are cars parked near the shoreline.
Shoreline from the lake
Boaters passing a wooden slide
Water skier
A couple walking on the beach, with the slide visible to the left