Actually Ozark Anglers does have an Osage forum, but it's in the tailwaters section and not the stream section.
The lower end of the Osage has largemouth, spotted bass, and walleye, along with various sunfish and the occasional white bass or hybrid striper. It's very dependent upon how much water they are letting out of Bagnell Dam (Lake of the Ozarks). It's flat water, very murky usually. If you go upstream 20 miles or more, it gets into what I'd consider better water, and if the river is fairly low it will be reasonably clear and easy to fish, but you'll need a boat of some kind to do it. The Osage isn't wadeable anywhere. There are some smallmouth in it as well, but not down close to the Missouri.
This year the lakes upstream have a lot of water due to lots of rain. Hopefully the lakes will be down to normal by the time you are there and then it all depends upon how hot it is and how much electricity Ameren UE needs to generate as to river conditions.
If the Osage isn't very fishable, there are a number of smaller, Ozark type streams in the area that can furnish good fishing by wading or canoe/kayak. Moreau, Tavern Creek, Maries River are all nearby.
