The DEC recently GPS'd the various designated campsites at Whitehouse area of the Sacanadaga Primitive Area along West River Road in Wells. This provides a pretty accurate map of the various campsite locations. West River Road isn't open to motor vehicles yet, but will open later in May once the frost is out of the ground and the dirt road isn't too soft.
Big Eddy Trail: Take the White House Connector Trail 0.2 miles to Northville Placid Trail. Head North-West on the NPT until you climb over a small ridge (roughly 60 feet ascent) and then bear right at 1/2 mile mark. Head 0.8 mile to two campsites and the cable crossing over Hamilton Lake Stream.
https://andyarthur.org/whitehouse
https://www.dec.ny.gov/lands/100874.html
This updated map contains the exact locations of campsites and boat launches along Mason Lake based on the DEC's GPS-based survey of the campsites last fall. While previous maps that I made up using heads-up digitizing and my own notes were fairly accurate, this map takes it up a notch.