The path is mostly the familiar rails-to-trails limestone. About five miles is asphalt-paved, starting from the town of Wasco. (You wascolly wabbit! Sorry.)
Most of the path is in such great condition it might as well be paved: very well tramped down and smooth. There was lots of bike and jogger traffic until past the paved bit, when it suddenly got very rural and isolated. Myriads of flowers along both sides: purple, white, red. Trail is fanatically straight and level: you can see the white limestone ahead of you for what seems like miles, all the way to the vanishing point.
The trail parallels Route 64 (North Avenue), so it can be a bit noisy, especially on a Memorial Day weekend when it seemed like every motorcycle in the state was heading west.
Between the "town" of Virgil (epicenter of the great Illinois quake of '10, magnitude 3.8) and Sycamore, the trail turns into an ATV track for a mile or two. Not an impediment, but you can tell you're not in suburbia anymore. A couple of short quarter-mile stretches of could be better-maintained.
Arrived in Sycamore very thirsty and hungry. After a stop at a gas station for a couple of bottles of water, I had lunch at the Dairy Dogs. Make sure you specify no ketchup on your "Chicago style" hot dog. (The stand was operated by a couple of 16-year-old girls who didn't know any better. Otherwise I'd have thrown a shit-fit. Ketchup on a hot dog. Jebus.) Otherwise, the Dave Berg dog was just OK, nothing to write home about.
I must be getting good at this: I covered 37 miles in 3 hours and 8 minutes, arriving at the car a sweaty and ready for a rest, but otherwise OK. This after a 20-mile ride the previous day!
Wish I had some pix but somehow I deleted them off the camera. Just imagine the Prairie Path, only straighter and flatter, with farmland on either side carpeted with three-inch emergent corn sprouts.