Sometimes an uncomplicated long walk is fine.
To find Rockwoods Range Conservation Area, go west in I-44 to the Six Flags Exit. At the light north of the highway, take a left (west) on Fox Creek Road. The parking lot is on the left, and is well signed. The roads are paved to the parking lot, which is the usual high-quality Conservation Department gravel (no irony intended--they take care of their property).
Google has it located:
The Department of Conservation's web site has the usual (and more than adequate) information about and directions to the area.
Rockwoods Range is a fairly big (1,300 acres) section of mostly mature forest. It's mostly hardwoods, although cedars do occur in patches, as they do everywhere. It's near some fairly populated areas, so it gets a lot of use, and it has a far suburbs kind of feel. When I was there, I saw trail runners, spandexed walkers, and horseback riders. I suspect it gets bike traffic too.
The Green Rock Trail, which starts at the parking lot, is for foot travel only. If it's rained recently, you'll want to stick to it, and avoid the trails where horses are allowed. I hiked part of the horse trail, and I was glad it had been dry--in wet weather, horses will turn sections of the trail into ankle-deep mud pits. Not pleasant.
I can't see myself going back to Rockwoods Range any time soon. There is cool stuff there--some impressive sections of forest, and a nice little creek--and the place obviously means a lot to people in the area who use it for exercise, or as a place to ride their horses. But I never seemed to get beyond the sound of the highway, and there are places just as close (LaBarque Creek CA, for example) which offer more varied settings. If I lived nearby, however, matters would be different: then I would do what those spandex walkers and trail runners were doing, and use Rockwoods Range as a place for exercise.