I rode this trail and the Trumbull section on May 13, 2011. I started at the northern most trailhead on Pepper St. and rode the short distance into the Newtown section. The Newtown section is very rough, but it is passable. It's only about a quarter of a mile long.
The ride South to Wolfe Park was pleasant and peaceful. A short detour onto Pepper St and then Grant St, which is a dead end, was easy to navigate. The detour is well marked. There's a large parking area at the intersection of Pepper St & Cutler Farm Rd. as well as the small unimproved area where I started from.
After reaching Wolfe Park, I went looking for the Trumbull section which was supposed to be about 2 miles down Route 25, according to Google Maps. After riding to the end of the Park road, I turned west on Purdy Hill Rd and then south on Maple Dr. Just before the sharp turn to the right, I spotted some signs that stated "Bike Trail" Following these signs took me to Victoria Dr. Turn east and go over the small road bridge, then cross the road to follow the bike trail, the Victorinox plant will be on your left. The trail will then cross Spring Hill Rd and you'll enter Spring Hill Park. Ride through this park and you'll come to Monroe Turnpike. Cross this and you'll enter Old Mine Park, which is the northern trailhead for the Trumbull section of the trail.
Though it sounds complicated, it was a fairly easy route to follow to get to the Trumbull section. It sure beat riding with the heavy traffic on Rt 25. Google map did not show the linking trail. I don't know why, because it looks like it's been here for a number of years and the previous reviewer rode on at least part of it.
After that it was an easy ride to Tait St, the southern trailhead. Quiet and peaceful with the sound of the river as your traveling companion. There were more people on this section of the trail, but it wasn't crowded. Parking is available at Spring Hill & Old Mine Parks as well as the southern trailhead at Tait St. Along the way, I saw several places along the river to stop for a break, which I took advantage of for lunch. Then it was a quick ride back to the car on Pepper St. All in all, a really great ride. 8^)

I've been biking the Trumbull section of this trail for a little over a month now, and set out yesterday to find the Monroe section. I first found it by following the directions here, and rode along Route 25 (Main Street) for a bit, then turned off onto Purdy Hill Road and found Wolfe Park. But on the way back, I found the "Bike Trail" signs which led me ride to the Trumbull section.

The trail starts out pretty typical, crushed stone and ballast, wide and level. There's a couple of picnic tables at the start. There's even a couple of park benches along the trail, if you need to rest. The trail seemed to end and dump into a residential area, but by continuing on the road for maybe a quarter of a mile, you can pick up the trail again. This section is a little more rugged and narrow. At one point, it was barely wider than me, but was lined with only little branches, so I had no problem getting through.

I made some nice discoveries on the later part of the trail. Like an abandoned rail line, with the rails and some of the ties still visible, running alongside the trail. A little further down, the trail actually crosses two tracks side by side. People have tried to make it a little easier to cross them by placing little wood ramps, but they're a little worn. But I was able to cross them without trouble. I like a little challenge, so this was one of my favorite parts of the ride. I'll post a picture of the crossing.

At the end of the trail, I found what appears to be a working freight rail line, with a private crossing to an industrial site. I'm also a railfan, so this was a nice find. The now abandoned sidings are also visible.

As I said, I was able to find my way back following the trail signs, and able to avoid busy Route 25. On Maple St., I found the old (1850) Stepney Depot, though the tracks are long gone there. Again, another great find.

Between the two sections, Trumbull and Monroe, I logged almost 25 miles round trip. A really enjoyable ride.

We rode the trail between Wolf Park in Monroe and the north end of the unimproved trail in Newtown.

The Monroe portion is wide and well groomed. There is a 0.6 mile detour on Grant Rd. and Pepper St. to get around private property.

Just north of Great Hollow Lake the trail goes through a cut that created a noticeable breeze. On some old maps this cut is named Windy Gap.

The Newtown portion of the trail is much narrower and although unimproved it was flat and clear of debris. Much of this portion runs alongside abandoned rails and the Botsford wye. I imagine this trail could get a little tricky once the foliage season arrives.

I proved that the Newtown section can be navigated by a fat old guy on a hybrid. I only got off the bike once to cross the pair of tracks at the south end of the wye.