This may be a tad bit off from what you are looking for, since I know nothing about MO, but...
Having done a bit of whitewater rafting, I would suggest you hold off a little on that. It isn't a cheap activity ($ or time). You pretty much will spend a minimum of $40 each, plus a minimum of half your day, no matter how measly of a trip you get out of it. You can spend a lot more, both time and money.
HOwever...
With your younger two being 7 & 8, you aren't going to find a trip rated over a Class III (3) that is likely to allow their ages on the trip. And a Class III trip is rather lame. Lots of work usually (lots of flat--which means rowing) for very little thrill factor. There is also normally a certain amount of work putting the raft in the river and hauling it back onto/up to the trailer (and every trip I've ever done, the paying folks--YOU-- are expected to help with this process.
I would research the age limits for trips with at least one Class IV rapids in it, and plan to go when your youngest is old enough to be allowed on the trip.
We love doing it. Favorite trip ever was on my honeymoon in New Zealand... 7 meter falls at the end (roughly 21 feet). It was phenomenal!! And probably illegal for public tours here in the U.S.A.
Updated
This may be a tad bit off from what you are looking for, since I know nothing about MO, but...
Having done a bit of whitewater rafting, I would suggest you hold off a little on that. It isn't a cheap activity ($ or time). You pretty much will spend a minimum of $40 each, plus a minimum of half your day, no matter how measly of a trip you get out of it. You can spend a lot more, both time and money.
HOwever...
With your younger two being 7 & 8, you aren't going to find a trip rated over a level III (3) that is likely to allow their ages on the trip. And a level III trip is rather lame. Lots of work usually (lots of flat--which means rowing) for very little thrill factor. There is also normally a certain amount of work putting the raft in the river and hauling it back onto/up to the trailer (and every trip I've ever done, the paying folks--YOU-- are expected to help with this process.
I would research the age limits for trips with at least one Level IV falls in it, and plan to go when your youngest is old enough to be allowed on the trip.
We love doing it. Favorite trip ever was on my honeymoon in New Zealand... 7 meter falls at the end (roughly 21 feet). It was phenomenal!! And probably illegal for public tours here in the U.S.A.