It's a beginner level trail, it elevation doesn't change too often, its got some bumps and it's pretty repetitive, it did get very overgrown so if it looks like a dead end its not, it will let out and lead to McDowell Grove Forest preserve.
Starting from the dam that you'll find after following the Dupage River Trail West, you'll go downhill facing toward the left side of the dam, from there, go through the tall grass, you should see a sign, and then the trail will follow the river until you hit McDowell Grove Forest Preserve
http://www.singletracks.com/item.php?c=1&i=8858