Albert Wisner Public Library in Warwick, Orange County, New York. I was researching an event that took place in Warwick- that post is forthcoming. The staff was helpful and knowledgeable. (And so were the other patrons with directions!) I made use of the local history room. I recommend asking for and visiting such a room whenever you visit a library. You never know what you may find. I found a 1924 book with grave inscriptions from Dutchess County, New York. You probably would not expect to find Dutchess County material in Orange County, but that is why I recommend browsing the "local" history collection yourself.
I found a listing for a small, private cemetery in Pawling for the Campbell family. This may or may not be the same Campbell family that I am following in Dutchess County, but now the possibility has entered my mind and can be explored further. A check of findagrave reveals that someone else has already ventured through the vegetation and photographed these stones, saving me from adding this cemetery to my ever-growing to-do list. In due time I may have come across this cemetery through other means, but that is true of so many of the treasures that we find. So check those local history rooms!