You're probably referring to the Water Co trails. We call them "Water Co." because the land is adjacent to United Water, which services Lambertville with drinking water.
Below is a link to a map I drew up of the place.
https://www.dropbox.com/s/1oiiahl04sowmds/water-co.jpg
If you enter from 518, it almost seems like you're trespassing, but you're not. The trail goes a longside a fence near a red barn. It's not very obvious that it's a trailhead.
Here's a link of how I link together Water Co / Greenway / Baldpate and Washington's crossing.
http://connect.garmin.com/activity/365153719
In my opinion, Water co. is way more fun than Baldpate. Baldtpate gets boring quick.
Note: this place is awesome when it's dry but stays wet in the low areas for quite a while. It's a little grown in at the moment and there's a few trees down that haven't been cleared yet .
Enjoy.