I found an old sketchbook I thought I had lost and it had a few of these sketches in it. As evident in the early scratch-sketch of the ranger, I had originally thought they might be the ones carrying a (much-larger) laser multitool instead of trail engineers. Only after really developing out the Anodyne/NPS relationship did I decide to split their activities.
The park signs didn't change much from these initial pencil sketches, with the exception of the earliest Anodyne sign. After seeing some of the signs around Area 51 and how multi-layered they had become, I decided to add additional panels to suggest that the "copepod" target sign was added -after- an incident.