Re: Washington Fly Fishing
I was out in Washington a couple of years ago, stayed about 60 miles NE of Bremerton in a little town called Sequim. During mid-summer some of the rivers can get a little thin in spots, but there is usually some good drift-boat combined with mixed shore-set-up steelhead fishing. Availability of fish depends on the water depth, weather, etc. - you know, just like anywhere else.
I booked a guide out of the Waters West Flyfishing shop in Port Angeles and had a great time fishing the Bogachiel and Sol Duc rivers. It rained most days (rain should be expected - after all, it is the Olympic penninsula!), but I hooked and landed steelhead every day I fished. There are some walk-in areas on the Bogachiel if you do not want to use a guide and/or do not have a drift boat; but if you want to walk up/down the river very far be prepared for some tough walking/wading. The river channels can get pretty narrow in some places (e.g. no real "bank" to walk on) and the wading can be over heavily mossed rocks cobble-stone sized and larger.
The steelhead were fantastic - big bright shiny chrome fish that fought very well. I only kept one fish for the entire trip (a 30"+ hatchery fish - had the adipose fin trimmed off for identification) and it was delicious! They were willing to hit an orange Stimulator, but we caught almost everything on a simple fly the guide provided us. I do not know if it had a real name, but it was a simple marabou leech pattern with lead-eyes for weight - maroon and red ones seemed to work the best, but color depended on the water/sun/etc..
Hope this info helps you. Good luck on your trip.