Parks offer many ranger-led programs, but there are plenty of activities for guests who prefer going it on their own.
All parks rent GPS units so that guests may give geo-caching a go. State Parks also run a Geocaching Adventure program with a different theme and new prizes every year. Some parks have fun GPS scavenger hunts and interpretive trails. There are many geocaches throughout the park system.
Many parks have brochures, guides and checklists for specific topics such as wildflowers and animal tracks. Parks offer backpacks filled with field guides, binoculars and other tools that may be checked out at no cost. Of course many parks also have well-signed interpretive trails and visitor center exhibits that highlight the given park's natural and historical features.
You'll find many of these activities in this website's park events listing, but call the park before your visit to learn about available self-guided activities.