The trail is singletrack for the majority of the distance. The main body runs along the Des Plaines River and has a fair assortment of technical aspects including fallen trees, small hills, creepy underpass and tight corning in tall grass. I would stick to the daylight hours for this course.
There are many points of entry for this trail. I typically use the one at the intersection of Thatcher and Augusta in River Forest. There is also a main entrance off Chicago avenue in between Thatcher and 1st Avenue. You can enter on either side of the street.
http://www.singletracks.com/item.php?c=1&i=1036