Prime time is right when it opens, but it is good all fall until it gets too cold over there.
Those fish are fun to catch but I always feel sorry for them coming all that way. Floats and Jigs work killer. Also #4 vibrax in metalic colors will nail them before the water gets to cold. If yer fly flickin articulated leaches on the swing drive them nuts, and nymphing monster stone patterns under an indicator has worked well for me...
Good Luck!!!

There is also a good chance of hooking a monster western slope cut, or a big bull trout this time of year....