Rocky,
Looks like a great trip!
I used to fish that portion of the Missouri quite a bit after moving to Townsend 22 years ago, but that was in the early days of "discovery," before so many people started fishing that stretch. It was pretty easy to find a good piece of water to wade, and there weren't many boats.
Eventually the pressure got to be a bit much, and that tot catch-and-release became prevalent. It seemed to me the really big fish (20+ inches) got to be less common. There can be several reasons for that, including RELEASINg fish, as any river can support so much biomass, whether X number of 4-pound trout or twice that number of 2-pound trout. That's what was found in the Bighorn after catch-and-releace became so much of a religion: There were more trout, but the average was smaller. Then there's always a mortality factor, even when trout are released very carefully, and it's greater with bigger fish.
The fishing's still great in the Missouri, but streams without as much pressure can also provide great angling. In fact I've caught trout averaging as large or larger on some smaller Montana streams too small to float. If you ever get up here again, we could try some of those!
