In Vermont I've had the best luck on disturbed sites. Usually when I see them they are in one of three habitat types:

Logging trail heads with lots of woody debris such as scattered bark and piles of logs and with decent sun exposure.

South-facing slate slopes on the edges of small bodies of water (spring-fed lakes for example)

Or along large power line corridors with rocky or woody debris. In the last power line corridor I searched Ring-necked Snakes seemed to be the most abundant species, even over Gartersnakes. The surrounding habitat was very densely wooded and hemlock made up a large proportion of the covertype.