Eric,
Spend some time on the MT side on your trip out or back for some angling on the Yellowstone, Gallatin, Madison if you can. (Don't forget Rock Creek as well!) I know for a fact that matching the hatch is critical, which is always 1/4oz. and 1/3oz. copper Little Cleos... That is if you want fish on every other cast. Browns on the spoon will be over 24" and every rainbow and cutt over 20"... and LOTS of them. "Piss on fantasy Ennis".
I like to fly fling with the 6# as much as the next guy but if it aint on top I aint doing it. That said if intent on fly only, stimulators, hoppers for the top, greased muddlers for sub presenting and bead head/weighted nymphs for the depths. Piss on the small "fantasy flies".
Have fun on your trip, watch out for plenty of moose, bear and buffalo if planning on some backcountry excursions!
