Eldorado State Park
Eldorado State Park, near Boulder west of highway 93 is a day use park which offers hiking between sandstone cliffs, picnicking along along South Boulder Creek and views of climbers on spectacular rock exposures. GPS at entrance station: N39° 55.923 W105° 16.839.
Here is their website. Phone 303-494-3943 Trails Map and Brochure
The Fowler Trail is a self-guided nature walk built for wheelchair use. There is one rather narrow spot, but I was assured that people negotiate it without problems. It is about 1/2 a mile long and has great views. Bring your own binoculars as the two telescopes set up for viewing raptors (or climbers) on the other side of South Boulder Creek are too high for viewing from a wheelchair.