I've fished the OP once. I stayed at the Kalaloch Lodge that Dillon mentioned. It is very nice and I thought reasonably priced accommodations. There is a lodge of 20 or so rooms and several individual smaller cabins where many of these are along the ocean. Very beautiful. I would suggest looking into an ocean front cabin if they're available.
The main tip I would have is find out when dinner is served and reserve a table. It gets full and they're not open late. After a long day of fishing.....a good meal is a nice treat. I missed out the first night.....I didn't again.
There are other hotels in Forks which is the epicenter of Steelhead on the OP. Another spot to stay would be at one of the many hotels/lodges in Port Angeles. All depends on the rivers you plan to target.
I fished the Hoh......it is a beautiful river. I didn't have any luck....but fishing the OP is not easy. Using a guide for your first day is a very good idea. One suggestion I was given for swinging is Jim Kerr and Ryan Bullock at Rain Coast Guides in Forks, WA.....these guys are busy so be persistent.
For fly shops.....I can recommend taking the time to visit, shop and chat with Anil at Pugent Sound Fly Co in Tacoma. The other would be Waters West in Port Angeles, WA. Never been there...but have shopped at their online store and they seem like great people. Which one you stop at depends on the route you plan to take to get to the OP.
The OP is a temperate rainforest and gets 150" of rain annually. It's the wettest area of the lower 48. Hence the reason for the volatility. I don't know if this is all of the OP or one particular side of it........ Watch water levels and rain forecast. I think it rains at some level 270 days of the year......
For rods.....any double hand rod 11' - 13.5' will work. I like a 7 WT personally and I bring interchangeable heads and sink tips to match the conditions....which on the OP can be highly volatile.
For flies....I personally swing flies and would suggest intruders, leeches or any of the numerous PNW traditional steelhead flies. Swinging up a wild OP steelhead with a Syd Glasso Orange Heron is definitely on my bucket list. Bring a wide variety. Think prawns / squid colors......
The rivers are short and not as wide as other Puget Sound and Columbia Basin Rivers. The rivers are trenchy....so fish the edges and swing hard to your dangle. 'Cast for show' applies here.
I will leave you with this final thought. Tragically...the OP is the last holdout for wild Steelhead in WA. The Sky, Skagit, Sauk, Stilly, etc are shells of their former self and there are rumors that low wild return numbers there might bring yet another closure soon to these rivers to protect these fragile creatures.
When I fished the Hoh.....I happened to meet with a Game Warden. I asked what typical wild return numbers are there. He said 5,000. I was quite shocked they were that low. If true.......treasure any opportunity you might have to connect with one fish all week.
I saw like 2 other anglers, a few drift boats... Most people were targeting the fish near the lower hatchery. Not what I was after.
The OP's secrets will not come easy to you.....Nor should they. Guys in the area keep things very tight lipped. You're not going to stumble onto one single site with all of the answers. Some local WA residents might even take offense that I've shared as much here as I have. The info I've shared really applies to any steelhead river if you've chased enough of them.
Buy a topo map and ask as many questions you can of your guide. Don't expect your cell phone to work. Be safe and be respectful of the rivers you might travel to. You will be witness to the power that these waters bring. It is truly a magical place.
