This is where President Harry S Truman used to vacation when he wasn’t molding post-WWII geopolitics. It's beautifully preserved and open only for guided tours, although you are welcome to visit one small gallery with photographs and historical displays (and a short video) on the ground floor.
Plenty of Truman’s possessions are scattered about, but the real draw is each of the guides, who are intensely knowledgeable, quirky and helpful.