D&R Canal State Park: north
off Quaker Bridge Road/Nassau Park Boulevard, Lawrence Township, Mercer County, New Jersey
NJ Turnpike to exit 7A for US 195 west; take US 295 north and get off at Exit 67 for Quaker Bridge Road; turn left onto Quaker Bridge Road and go over Route 1; turn left onto Nassau Park Boulevard; cross over the bridge spanning the Delaware and Raritan Canal and immediately turn right; look for the parking area on the left near the intersection with Quaker Bridge Road. (I don't exactly know where the entrance is, but this is the area.).