I returned on one of those great Midwestern fall days to complete the portion of the Glacial River Trail south of Jefferson. I found the few miles that were in-fact a former railroad. The rest of the trail is in the WI-26 freeway corridor or on rural roads and city streets, but the trail is all paved.
The city of Fort Atkinson is very attractive with trail amenities including public art. I again found that the TrailLink map was a necessity as the signage on the tail is sparse.
My only negative is there is no need to do the on-highway portion south of N Wright Rd unless you want to continue to the connection to the Spring Brook Trail that will take you into Janesville.
For an out and back trip consider places where you can use the parallel old WI-26 for a different landscape view.

Plenty of space to park stock trailer in gravel lot on Lake Shore Rd Clinton. Cute little covered bridge in small park with picnic tables was the start of my mule ride. There were trash receptacles, handicap accessible restroom & a wood post hitching rail. Many "sponsored" rest spots with wooden benches, picnic tables & some had roofs along the flat trail. Trail bed is wide, flat & firm as small crushed gravel & grass base. Views of plant/tree farm & rural properties after brief bit of SE side of Clinton. Mileage markers. Several blacktop road crossings. Easy, well-groomed trail. Small gravel lot at east end with trail map on kiosk. For lunch at Boar's Nest Bar ride Hill St (right uphill), stay right on Clinton St, quick Left along west side of the Park 1 block to stop sign Cty X. Ride directly across Cty X then straight across grass to cable picket line.
I-43 runs parallel to trail. Loud traffic but distance kept equines from becoming unnerved 🙂 Met a jogger, a hiker with a leashed dog on trail & 2 bicyclists at covered bridge. All were respectful of equines.

If you are looking to take it easy and just go for a nice ride this is it. Smooth and simple. Very well maintained.

The Glacial River Trail in the Rock River valley is untypical for Wisconsin state trails in that it is entirely paved and not a rail-to-trail. It has a great mix of segments in the WI-26 freeway corridor, city streets and rural roads, with some good grades. I did the north part of the trail from Jefferson to the junction with the Wild Goose State Trail. There are no services provided by the trail owner, but the trail is free to use. The signage for the trail-turns is minimal so the Trail-Link map downloaded on your smart phone is a must. I especially enjoyed my ride thru the river towns of Jefferson, Johnson Creek and Watertown, where I took the time to ride around the downtowns. I will come back someday to do the south portion.

We got on the trail at Lacy Street in Verona/Fitchburg WI. The trail was paved and in great shape at that point. Cyclists were using it as a commuter trail and there were several people out walking and running. The trail turned into non-paved surface and that is where we dismounted to pay the fee of $5. Oh my, what can I say. The trail is NOT crushed limestone. At places it appeared to be an abandoned trail except for the path made by a bicycle tire. It was a muddy, sticky mess. I had checked ahead of time and found out the Stewart Tunnel was closed, which saved us back tracking since there wasn't a sign indicating the tunnel was closed. We detoured onto Tunnel Rd and took various paved roads into New Glarus. The best part of the trail was the Monroe WI segment. There was a detour off of the trail as we were coming into town. Very good signage directing us through the road construction area. There was a very nice trailhead with a drinking fountain and restrooms as you came into town from the north. We continued to the downtown area and decided to take a break and headed to the Dairy Queen by exiting the trail at 5th Street and riding to 8th Street. It was a challenge to cross the street but it was during lunch hour. As we headed out of Monroe there was an area of very loose gravel vs crushed limestone. An inexperienced rider might have wrecked. The rest of the trail was not maintained until it connected with the Jane Adams Trail. It was is good shape into Freeport IL.

Parked at Cottage Grove today and biked out 23 miles and then back to car. It was annoying that we both paid our 5 dollars and then visited the rest room. No toilet paper in mens or women's and both stalls in women's were smeared with feces. Nice surface on trail. Not enough benches. This trail would definitely not qualify as a national rail trail.

I grabbed the trail north of Janesville on my road bike. Crossed the bridge over the highway and did about a mile on the county road before winding through a new housing development and finding the actual trail. It's in great shape, lots of gentle rolling hills and a couple of roundabouts but not a single person anywhere along the trail. I rode to Milton and most of the trail parallels the highway so it's loud on one side but beautiful and agricultural on the other side. I saw hawks and finches and no humans of any kind. It was pretty sweet. I only gave it 4 stars because of the highway driving . Otherwise it's a 5-star paved trail.

It seems to me this should have been called the Hononegah Trail given it passes through the forest preserve and etches the road with the same name. Anyways, the far east part of this path stems off of the Old Bridge Trail which is a great place to bike. When you come off that trail and onto the Kinstone, you go through a small forested area before heading up a hill that starts you along Hononegah Rd. The trail is asphalt/cement and is in pretty good shape. As mentioned, it goes through the front section of the Hononegah FP where they have a bathroom, picnic tables and a water pump all near the trail. The trail ends just east of downtown Rockton but another path picks up that takes you past the Rock River and the downtown area.
There aren't many bells and whistles along this short path but it is a nice continuation to other trails in the area.

A month or so ago I rode the full length of the Long Prairie Trail. When I reached the Ronald Olson FP I realized that the trail continued as the Stone Bridge Trail. Having liked the Long Prairie Trail I marked the path for a future visit. That didn't take long, I was back a month later and ready to tackle the Stone Bridge and four other paths in the area with my son.
The Stone Bridge Trail is a very well kept limestone trail that only spans about 6 miles. Although short it features areas where you are in a gorge, then on a steep hill. In the middle you can get a history lesson by demounting and walking down the hill at the Stone Bridge site. At the base of the hill you can see the preserved site and read about its historic value.
At the northern base of the trail you can see where the train track line continues north. I sincerely hope they turn this into more biking trail that heads into Wisconsin.