>>2811359>KansasTallgrass Prairie National Preserve in the Flint Hills has a pretty awesome trail that had a herd of bison blocking the way, I had to go around them. I also enjoy the Baker Wetlands in Lawrence, but none of the trails get anywhere close to your 10 mile requirement.
>IowaThe different units of Loess Hills State Forest are pretty cool, I went during fall and the bur oaks were beautiful. I boondocked in some guy's cornfield around this area once.
>NebraskaThere are some Loess Hills preserves here like in Iowa, haven't checked any out yet but I plan on boondocking in some cornfield here next month.
>MissouriThis is where shit gets real. Mark Twain National Forest has a shit ton of banger hikes. I like the hikes in Devils Backbone and Hercules Glade. Ozark National Riverways is gorgeous and has several long trails worth hiking, and it's right in the St Francois Mountains which are beautiful all year but especially in the fall. Not to mention all the MDC lands, with Busiek State Forest being my favorite.