The time frame your up there the Situk is the river to target, the Lost has a later run of fish. We were up there in July and there were a few chum and pinks in the Situk already. Going after silvers with a fly can be fun but you weed through alot of the other fish also, which isn't a bad thing but it gets a little tiresum after a while. We caught silvers while we were halibut fishing when ever the bait would go past we'd toss a spoon out and wham. The silvers were in the 8-10lb range so thats a good indication you'll be into some heafty one's on your trip. Remember to make alot of noise if your walking the river trail. Good luck and have fun.