This is one of the most open, beautiful parks I've been in. It's about 16 km from entrance to the…read moreold dam. The road winds it's way close to and across an old, usually empty riverbed. There are a variety of well-marked and mapped hikes, climbs, and bike paths.
There is a lot of activity in the park, even after dark. I recommend driving through it, even if you're not interested in getting out to explore it on foot.
Also, this is not a pristine, sterile public space. There are private homes, businesses, and communities within it. That is off putting to some, but it does help keep the space active and somewhat cared for despite government neglect.