The Ozark Riverways offers a few facilities for the mobility impaired. There are wheelchair friendly picnic tables in the major campgrounds and picnic areas and the newer restrooms and showers are wheelchair accessible.
There are a few trails that are level and paved with gravel. These may be accessible depending on your abilities and equipment. Specifically these are the Slough Trail at Big Spring, the access trail to the actual spring at Big Spring, and the trail to the Round Spring. While not strictly speaking in the park, there is a boardwalk at Watercress Campground, located just past park headquarters in Van Buren that will help you access the river bank and even try your hand at fishing from a wheelchair.
A new ramp at the Alley Mill makes this historic site easier to access. Park offices at Van Buren are accessible as well.