Quadfisher,
I have insulated bootfoot light weights. I'd say they are the way to go but I hate neoprenes and wading shoes are not warm enough when water temps get down in the 30s.

I fished the Salmon River, NY in winter and was quite comfortable with only one pair of (inexpensive duofold) underwear with fleece over the top of that then a lightweight shell to keep the burdocks from sticking. No jeans or other pants of any kind...but I'd like to try Lady Fishers silk idea as a first layer. The jeans, however IMHO are a mistake.

I have lots of experience with Cold-Dry weather but not too much with Cold Damp. You can have both in Montana. I have spent 2 1/2 years in Antarctica including 6 months at the geographic south pole. But both climates share this: Its better to dress and be a little chilly than to dress to the point of being comfy. Once you start moving, you're going to start sweating if you're over dressed. Then its chill time when you stop to fish! Its tough to dry out and get warm again in the Cold-Damp fishing environment. Just ask any one who has fished Cape Cod in the fall. (thats the coldest I've ever been)

Hope you catch a bunch,
Ol' Bill