Elinor Bedell State Park

Elinor Bedell State Park 
This state park near Spirit Lake is on the shore of East Lake Okoboji.  In addition to hiking there is swimming, boating and fishing.  Trails are paved, but call to be sure of conditions 712-337-3211.
Here is the DNR’s website  and the more informational website from Iowa Parks.
Wheelchair Accessible“The park includes an extensive system of paved hiking trails. The trails are accessible to all entrance points connecting activities and points of interest. A raised boardwalk will take park users through the wetland areas and along the lake. The system is approximately 7,500 feet in length, paved, and accessible for persons with mobility impairment.”