The Hillsdale, NY public library has a ton of information on both the murder the trial. I've become interested myself in the events, and I've made copies of some of the court transcripts. I don't recall seeing any 1800's news clippings on the murder from the library, but I do intent to do further searching myself.
Also, FYI, there is a very expensive development that is now for sale in the Town of Austerlitz which I believe contains the site of the murder. The site address is: "http://www.baldmountainreserve.com/
" and shows the "Alford Pass" (you need a good monitor or good print to read its location).....the murder occurred 1000 feet from the NY/MA line and the cabin was on a creek. I'd speculate that it was on a creek on the Alford pass, since both Vandercook and Beckwith came and went from Alford because it was the closest settlement.
Hope this helps!