The NJ Trails Association is your best source of information:
MapNew Jersey Trails Association
You will find that many of the trails that they list are located in sprawling Franklin Township, which can be accessed from Woodbridge in ~35-40 minutes, via I-287. I use the trail adjoining the Delaware & Raritan Canal several times each week, and I occasionally hike the trails in Six Mile Run State Park, The Negri-Nepote Grassland Preserve, and the Griggstown Grassland Preserve, all of which I can recommend.
Also--Duke Farms, in Hillsborough, has miles of trails for your use:
DukeFarms
If you want to go a bit further, the trails in Lord Stirling Park (in Bernardsville) are extensive and include wildlife viewing blinds:
http://hikenj.net/parks/lord-stirling-park/