Check out
SwimmingHoles.info New York Swimming Holes and Hot Springs rivers creek springs falls hiking camping outdoors
It's a little outdated, but provides a review of swimming holes and sunning spots in New York. Has information on if nudity is allowed, tolerated or prohibited.
Personally, I use to hike up several mountains in the Adirondacks. Always choose lesser traveled trail as they generally had few families and kids using them. Found most nature hikers in these terrains are more tolerant of others sunbathing. Had a few stumble on to me and join me for sun and fun.
Actually swimmingholes.info covers other states as well, just go to their home page.
As a reminder, you live close to Vermont which still does not to my knowledge have a state ordinance prohibiting public nudity. It is up to local towns to pass their own law. Brattleboro was famous as few as three years ago for people nude sunbathing in downtown parking lots. Note: sprouting a boner or engaging in sexual activity is another matter.