I have hiked pieces of this path several times. It starts in Kishwaukee River Forest Preserve heading north along the Kishwaukee River and then turns to the east through the center of Blackhawk Springs FP and ends up along the eastern side of the FP where it turns south and ends up crossing the river at the far SE corner of Blackhawk Springs.
It is paved and well maintained. I have crossed it a number of times while hiking and there always seems to be people out enjoying it. The scenery is nice. Kind of a park like setting mostly.
Unfortunately, you get to the end of the path and it just ends. There is no good way to get back where you started without retracing your path if you are on a bike.
Hikers have a lot more options as there are hiking trails one can take inside Blackhawk Springs FP that one could take back most of the way without retracing your steps. The path also provides access for hikers to Espenscheid, Oak Ridge, and Deer Run FP.
The access is not always real obvious. There is a gravel service road at the path where it turns south along the eastern edge of Blackhawk Springs. If one takes the gravel road to the east about 100 yards, one can cross Perryville Road and enter Espenscheid. You have to go north along Perryville for maybe 50 yards, cross and then come back down and look for the unsigned trail head, but it is right across the road from where the gravel service road touches Perryville. There is a one lane mountain bike trail that one can access there as well as hiking trails. The mountain bike trail is not on the trail map but is well maintained and signed near the preserve entrance to the north. It is a loop that has a lot of zigs and zags but if you keep going you will eventually get through it.
There is also a hiking trail (on the park maps) that goes under a bridge in the SE corner of Blackhawk Springs that gives more obvious access to Espenscheid for hikers.
If you take the path to the end at the far SE corner of Blackhawk Springs one can walk north along Perryville Road to get into Deer Run FP, or south to get to Oak Ridge. Neither access is real obvious, but it is there for hikers. You can also ford across the river under the west set of power lines that go north south through Deer Run and Oak Ridge. The ford is for horses but is not real deep and is gravel bottom there. It is not yet on the park maps but is well signed.
You could probably loop through all these preserves on foot doing 30 miles or more and never see more than a few miles of the same trail sections.
If you decide to do a hike in Deer Run, don't forgo a pass through McKiski FP. It is located to the north of Deer Run and there is no access to it except by horseback or on foot. It is a 2+ mile hike through Deer Run just to get to McKiski and the trail there while it is well maintained, is not on that park map either. It is a nice hike through the flood plain forest there that you would not want to miss.