Elmhurst is about half an hour away from Waterfall Glen, longer if there’s traffic. So it’s not really near his house. Interestingly enough, if he were to drive from Elmhurst to Waterfall Glen, I would assume he’d park in one of the entrances near Cass Ave., as they’d be closer to Rt. 83 (which is a straight shot from Elmhurst to Waterfall Glen). He could have parked on the other end of the preserve if he wanted to avoid crowds, I suppose, as the “waterfall” is closer to one of the Cass Ave. parking lots & that’s where most people congregate. IMO: I almost feel like the car was ditched in that lot.
The Lemont quarries butt up to one edge of the forest preserve, as does the Des Plaines River. They may want to turn focus onto those areas.