PaddleIraq is right. The Shoshone river through Cody is still hanging in there, 1000 cfs. it has a six mile section,(which is most scenic), or continue on to the next bridge to make it 12 miles, all class II, with one borderline III on the lower.
The Northfork of the shoshone is LOW, but fishing rafts have been going down the lower part, from the forest line down to the reservoir.
I second the Bear trap canyon section of the Madison. Pair it up with the Yellowstone through Yankee Jim Canyon and it might be worth it to drive from Sheridan.
There isn't much flowing around Sheridan this time of year, esp. for a cataraft.
call me if you get to Cody