Re: Mid-late November Montana
The Clark fork is open to fishing year round, so no worries there. The tribs are what close, so definitely check on those. I'm not familiar with water close to the ID border but the lower Clark fishes great down to Superior.
As for better spot than others, yes the Clark is definitely a river that has better sections than others. Unfortunately I don't what they are down there, I've only ever floated down to St. Regis. How far into Montana are you willing to come? The other thing is the lower Clark Fk is better floated, its a pretty big broad river. But it will be low and it is fishable on foot. Don't let the size scare you away. Most of the fish are on the banks anyway, at least in the summer. You could run into small Baetis and midges hatching. Walk the bank and watch for noses, the Bows in the Clarky are notorious for podding up. Its not unlikely to see a dozen very nice fish rising in one small area. It's awesome fun when you find them.
As for small streams, check if the St. Regis River is open, I-90 run along it on your down into MT. So you have deal with interstate noise but its a nice little stream.