As I said I am from Missouri. I have traveled the State for over 25 year on business and even longer for pleasure. I have visited every county in the state many times. I believe I have visited most of the State Parks and State Historic Sites. I have also visited many lesser known sites such old grist mills/dams, battle fields, cemeteries.
If there is something that interests you please let me know. Maybe I can help or at least head you in the right direction.
A couple of general thoughts:
There is very scenic riding along the Mississippi and Missouri Rivers. Consider either as part of your route to Sedalia.
Don't bypass north Missouri. The northern part of the state has beautiful rolling hills and you will have it all to yourself.
Missouri has some very historic towns that are worth visiting. Hermann and Ste. Genevieve are two of the best but so is Washington and Hannibal and many others.
Missouri has 1000's of springs. The largest in the country in Big Springs in Southern MO
Navigating St. Louis can be a nightmare. Consider taking the ferry across the Mississippi River just north of Grafton, IL (N of STL) or Ste. Genevieve (South of STL).
KC is not as bad as STL but skip it if you can.
MO was the third most fought over state during Lincoln's War. There are historic sites everywhere. And if John Brown and Bleeding KS interest you there are sites all over eastern KS. (The war started in KS 10 years before Sumter.)
I also am very familiar with KS, especially the eastern 1/3 that includes the Flint Hills.