They call Chinook Kings in Alaska. The Bristol bay area is the most targeted area of sport fishing & for good reason. I gets huge runs of fish. You hear a lot about the big kings on the Kenai Penninsula. Yeah they are big, but its combat fishing elbow to elbow, gear fishing. It's crowded because you can drive there from Anchorage so that is where the locals go to fill their freezer.
Most of the Bristol Bay drainage in flat tundra country. if you're looking for trees & wooded areas, that would be the east coast where Alaska comes down along side Canada. Now don't get me wrong, the Bristol bay area is a fantastic fishery. If you are fishing close (say within 20 miles) to the sea, the fish are full of piss & vinegar & an adult Chinook is a hand full on a fly rod. But the commercial fishery is there too. A lot of the lodges, even fly fishing lodges, fish for kings with conventional gear.
I've been to Alaska four times, mostly the Bristol Bay drainage. The first trip was the best, perhaps because I was rather naive about the whole thing & had never caught anything bigger than three or four pounds, especially on a fly rod. Twenty years later & after about ten years fishing steelhead with a two hander, I returned to the first lodge I fished up there. The fishing was still good but for some reason, the magic was gone.
Sometime after that first trip, I got to digging around & found this place. Flywater Adventures
This one always turned me on. Especially the mother ship expedition. Alas, it remains on my bucket list
is all about fly fishing, & the guides are all fluent Spey types. Many you will recognize from the Speypages. The accommodations may not be first class, but I've heard good things about them. (still on my bucket list)
Do you homework. That's part of the fun. Have a great trip.