1. One fly for all winter on rivers a. thru d., I'd pick a size 2 marabou streamer. If I am limited to only one color for that fly for all season and all the rivers, I'll choose purple.

2. I've never caught a steelhead by nymphing, altho I intend to some day. I swing flies on rivers a., b., and d., and have found only a couple spots to do so on c., the Salmon. Consequently I don't fish there much.

I wouldn't use my fly pattern suggestion as the basis for a plan of attack. My suggestion merely answers the question of what to do if you have to get by with one fly pattern. I don't actually use a purple marabou much in the winter, but I know I could fish effectively with it and even nymph it with a split shot on the leader. And it's quick and easy to tie. When I go fishing, I'll just use whatever's in my fly box.

Sg