Buses from NYC and Albany go to the nearby town of Kingston and less frequently to Woodstock town itself. See link for Trailways buses. There is also a frequent Amtrak train service from NYC that stops about forty mins away from Woodstock in Rhinecliff. Local taxis to and from Kingston and Rhinebeck are available.
https://trailwaysny.com/bus-from-woodstock-to-new-york-city/