Interesting thoughts by Brad Klein and Ron Whitten on how to determine if Ross spent time on various sites. I've never been to the Tufts archives (Givens Library section (?) although I have spoken to Khris a number of times).
If there is something there to prove he spent time on a various site that would be very indicative, I would think, but failing that, anyone, no matter how well they think they know Ross, is into just making assumptions.
The only other way to prove he was on site is to have that validated by club records or minutes. Receipts don't really do that.
Gulph Mills G.C. (Ross 1916-1919) has a little book by Willing Patterson that is basically a history of the club from 1916-1976 that used the club minutes to reconstruct not only the construction of the course but everything else that followed until 1976. GMGC had a member who spent full time with the construction of the course and his correspondence in conjunction with the Board Minutes (all the committees reporting) is clear indication that Ross spent three days on the site in the beginning. He then returned about ten years later for a reanalysis of the golf course and made various recommendations on about 2/3 of the holes, most of which were followed. This kind of evidence is the best proof you can have that Ross was there.
It's also interesting what Ron says about Ross possibly doing topo designs and never actually visiting a site. I very much believe that! The best evidence of that is Ross's career routing theme! It is extremely identifiable with almost every Ross course I've ever seen. It seems also to be a theme that never really changed throughout his long career.
Basically that routing theme was to identify every single high tee, valley fairway, and high green site any property had to offer. This does not mean that every hole was this way because of course it couldn't be (if you understand anything about routing). But the fact is that most of his courses have as much of this as the site could ever offer. How did this happen? My feeling is Ross would analyze the topos, identify the elevation numbers, measure (adjusting for scale) and with the high tee sites (or green sites) he would simply count up and down the contour elevation lines and rout and build as many holes according to this theme as he could. Sometimes understanding how elevation lines swing here and there from uphill and downhill into sidehill and side slope is a little tricky but obviously Donald was very good at this, very practiced and experienced! And when he came to the holes that needed to "connect" to this basic routing theme that were not of this type topography he was very good at that too.
Ron might be right that Ross sort of pulled holes out of the drawer when he saw similarities on a topo but I think Ross was quite clever about that too. When Ross recognized the topographic similarities he had the good sense to rearrange the "notes" or "features" (all the architectural elements available to him--bunkers, green shapes and contours, orientations etc, etc to disguise those basic hole similarities!
There are some general similarities of playability to this theme on so many Ross courses. The theme has always had the affect of making his courses play longer! Ross was a high tee, valley and high green site designer--there is no doubt in my mind about that. His holes that run ridges are much rarer and are actually quite interesting because they are rarer. Best example might be Seminole's #4! From tee through green it's a basic but brilliant design! More proof that Donald Ross was very very good!