Ouch! That's tough. Last time I looked, Ft Smith wasn't anywhere near the Madison:clown: As in, that's a long way to go for plan B.
My friend lives in Billings. By design, we spent two days on the Bighorn before driving to W. Yellowstone for the remainder of the week. Even with the fall weeds, we often get great streamer fishing on the Bighorn. Unfortunately, it was 70 degrees with bright sunshine and the trout weren't in a chasing mood. I had to hold my nose and nymph the second day.
Spent last weekend plus friday and Monday on the Bighorn, it was pretty damm weedy. We made the best of it though, averaged 10-20 fish a day, nothing huge, a few browns in the 19" range here and there though. The runs we found that were weed free produced a lot more then those that were clogged. I'd never been before, hope to hit it up again a different time of year.