I fished the Middle Kenai River area. While I didn't use a kayak, I was scouting the area to make a potential run at it with my Kayak.
We spent the first four hours looking for big fish. Between three people we only managed one fish but it was a beautiful 27 inch rainbow. It was caught on a creamy orange colored 8mm bead that mimicked the tons of dead pink salmon eggs.
At the end of the day we had seen some pinks spawning in a shallow stretch of the river and had seen some folks pull out a few smaller fish. So we waded the area and proceeded to hammer smaller rainbows and Dolly Varden fairly consistently for the next hour and a half.
Definitely doable on a kayak. I might have to give it some consideration if the weather in homer doesn't hold up. I hear the kings have been caught fairly close to the spit.
Here's two videos. The first is of the 27 inch rainbow my friend caught. The second is the smaller fish I caught at the end of the day.