I don't know where you're going to float, but some areas of the Niangua don't have a lot of G-eyes. You might have to eat trout. A good quality #8 is generally my choice, but #6 isn't bad. I like P-line Premium, but all the P-lines excel.
As far as one rod, I would have an extra 2 piece 5 or 5 1/2 spinning rod tucked in somewhere because accidents do happen. A Berkley lightening is a good candidate, they're light and don't have guide inserts to get knocked out and their cheaper than their quality in my opinion..