I’ve paddled on a number of sea kayaking trips in Alaska, including in Prince William Sound, Kenai Fjords, Kachemak Bay, and Glacier Bay. All of the kayaking trips to Alaska have been small, self-guided, 2 person trips with my wife, Ruth. They usually end up being about a week long. We bring a tent and some large tarps to stay dry, sometimes camping in a random place on shore, but I do recommend the Alaska Marine Park sites–not very fancy, but they do have wooden platforms to pitch tents, sometimes a metal box to keep bears from getting your food, and maybe a pit toilet.
While it is very beautiful, it is still wilderness, with all of the significant hazards, especially if you are doing a small, self-guided trip. Some locations can be very remote, with few other people, and rocky coasts. Weather is typically rainy and cold, sometimes stormy. The seas have large tidal ranges (in Prince William Sound, the tidal range between low and high tide can be as much as 5 meters), producing strong currents (1 to 3 knots), and in conjunction with high winds can produce big waves, surf, and confused seas. Water temperature is cold (40-50 degrees F), so capsizing can result in hypothermia fairly rapidly. I have typically seen a few black or brown bears on trips, but I’ve never had a problem with them.