Only a 20 minute detour from our main route, Mingo National Wilderness area is worth a quick trip. You can see all this area has to offer, and hike the ~2 miles of trails in an hour or so.
The visitor center offers some child-friendly info as well as a few short informative videos, explaining how Missourians have devastated every square mile of the state in their thirst to cull the land to make money from farming big industry crops. Mingo is one of precious few tiny tracts of land that have been purchased to allow the government to refurbish a mini habitat to reintroduce some of the original species that used to thrive in Missouri. No mention whatsoever of the original native peoples who were here before the Europeans arrived and took ownership.
The main and longest hiking trail in Mingo consists of a 1 mile boardwalk through some swampland. We were lucky (and quiet enough) to see one deer and a beaver. Well worth the easy mile walk.
The rest of this Wildlife Refuge is apparently only for hunters and fishermen to enjoy. Still, Mingo is (today at least) a nice quiet getaway with no more than the usual amount of expected mosquitoes.