I'll add my 2 cents..
KC makes a great FIRE spot. Cheap cost of living, lots of cheap and free activities available--especially if you like watching sports (Chiefs/Royals/KU bball/MU football/Sporting KC--people love to cook out and watch the games here), are into arts (several free galleries, a monthly art walk and several fairs throughout the year) or music (lots of great venues).
You have to be intentional about finding a place to live that's walkable--yes, someone here has mentioned great lake living but most likely you have to drive to everything for that privilege. The city is very spread out--we are huge soccer fans but who wants to drive 25 miles to watch the games? Personally, not me. Anyways, there are several very walkable neighborhoods, both in KCMO proper and most suburbs have little downtowns as well but you just have to be intentional about seeking that out if you want it (walkscore is pretty accurate here). Also I would say there is some hostility to bikers here--same as everywhere but it makes me nervous. To get very specific about walkable areas: Downtown, Westport, Brookside and Waldo in KCMO. Mission, Downtown Overland Park and center of Prairie Village on the Kansas side. Downtown Lee's Summit, Downtown Liberty, North KC (really great--probably where I would go if I had to do it again), downtown parkville. I'm sure there's more but that's the scope of what I know...
Sounds like schools wouldn't be a factor but don't believe the hype, there are decent options everywhere you go. Yes, even in the KCMO school district which has magnets and charters as options (we have mandrin, spanish and french immersion, montessori and neighborhood schools all available for free--not bad for a "failing" school district). If you don't want to be acitvely involved in seeking a good school, you can't go wrong in Lee's Summit, Liberty, Park Hill, Shawnee Mission, Blue Valley or Olathe.
Coming from the East coast, this city seems so catered to people with kids. So many youth sports and activities, family friendly restaurants and just kids, kids, kids everywhere you go. And it's easy to get around with them, so that helps a lot.
We do miss having easier access to decent hiking and outdoorsy things but you can certainly make do--the lakes are a few hours away, as well as a lot of canoeing and many people vacation out to Colorado which is an easy days drive. There's a decent mountain biking and trail running community and a few people that climb on the bluffs out by the river. There's even a kayak race down the MO river once a year. You have to seek out the communities for each of these things but they do exist.
I will say, coming from a larger city, I am surprised by the segregation of this city--it's bright-lined straight through the city and people will tell you not to live one place or another based on who you are. It is built into the fabric of the city and people don't seem to even think about it or make much of an effort to bridge the gap. It bothers the hell out of me but we do what we can to be good neighbors to everyone in the city. Some of the Missouri suburbs (Lee's Summit for example) are better mixed, but, just something to know.
Weather-wise, you just get the depth of all four seasons, for good or for bad. Tornadoes aren't that big of a deal--I think 2 have hit the entire metro area over the past 100 years and those haven't been big ones--but there are storms and a basement is good (though it also means dealing with inevitable wetness in the basement).
Anyways, I mostly love it here, just know what you're looking for before you move--possibly think about renting for a bit to get to know neighborhoods before you move