I also have ancestors from Sullivan County (Town of Rockland) and adjoining Delaware County. The Gregory family appears often in records and goes quite far back in Delaware County (try the Towns of Andes & Walton). Genealogical records for Delaware County are more numerous than for Sullivan. The Delaware County genealogical site is an invaluable resource. Try googling individual names with town of residence. I have often found links to cemetery listings using this method. It is a beautiful area in the Catskill Mountains most noted around the world for fly-fishing. The Fly-Fishing Museum between the villages of Roscoe and Livingston Manor is a must even if you don't fly fish. The history of fly tying has roots the area. Early occupations in the area were in the logging (making use of the rivers to transport logs), tanning, and farming industry. I am originally from Delaware County. Hopefully you will get a chance to visit the area. The mountain colors are beautiful in the fall. The area has been hit hard by floods in recent years but they (we) are resilient people. Many people from Long Island have relocated or have 2nd homes in the area. Roscoe has one of my all-time favorite coffee houses. The Woodstock area (actually Bethel) with museums and musical events is also nearby.