If you’re really interested in tracking down the Corkscrew, you might want to try and get your hands on a couple of out of print Rutland books done by the late R. W. Nimke, specifically Volume IV on the B&R and Corkscrew Divisions , Volume VII The Addendum (20 pages of it, anyway), and the Spurs and Sidings volume. Photo coverage of the Chatham Division is quite comprehensive (though quality can vary a bit), including shots of the last freight, as well as the scrapping of the line. Track and siding diagrams are covered in both Volume IV and the Siding and Spurs Volume; the latter includes some topographical maps, though.
Also, the town of Petersburgh, NY put out (1991) an interesting soft cover photo book called “Petersburgh, Then & Now” by Peter R. W. Schaaphok, which has couple of railroad shots in it that may be of interest to Corkscrew aficionados, particularly if you’re trying to find where the ROW went in the Petersburgh area.