Adam,
The Donald Ross Society website says that Ross was not onsite for this course. That would mean that he did this through drawings with topo maps. He dispatched lieutenants like Walter Hatch to supervise the jobs. From what I've seen of his drawings for similar work at a similar time (Wellshire GC in Denver, 1926), his work on these courses was far from "mailed in." He carefully designed the courses using the natural features available.
This is what the DRS says on its website:
"During his summers, Ross started designing and building courses throughout New England. Eventually, his practice spread into the Midwest and down the Southeast coast. In association with design assistants J.B. McGovern and Walter Hatch, Ross maintained a summer office in Little Compton, Rhode Island and satellite offices in North Amherst, Massachusetts, and Wynnewood, Pennsylvania.
Of all the courses that bear Ross' name, either as original designs or as renovation projects, he probably never even saw a third of them, and another third he visited only once or twice. Given the constraints of train and car travel in those days, repeat visits were difficult to arrange. Though Ross was a voracious traveler, he did much of his design work from his home in a cottage behind the third green at Pinehurst. There he worked from topographic maps, drew up blueprints, and wrote simple but sharply-worded instructions that his construction crew knew how to implement. "
You could probably find out more about this by sniffing around your club's or the town newspaper's archives.