Open year-round, the Decision Point Marine Park offers you and your doggo a single, public use cabin, as well as four tent platforms that are located nearby in Squirrel Cove. These platforms can be accessed from the cabin by a trail. You can only access the Decision Point Marine Park by float plane, boat, or water taxi, so you and your pup should be prepared for a trek.
The cabin and tent areas are primitive, as we noted, so it's important that you come prepared. Expect two full sized bunk beds, an eight-person sleeping capacity, a table, benches, counter, and an oil stove. That's about it in the way of amenities, however, a pit toilet is available a short walk from the cabin. You're able to reserve this spot, and a backcountry camping permit will be required to do so. You are responsible for all of your supplies.
While your dog is certainly able to join you, it's recommended that unless your pup follows strict voice commands, you keep them on a leash at all times in order to best protect them from dangerous wildlife. Never allow your dog to make a mess without cleaning it up - this will attract dangerous wildlife as well. If your pup is allowed to wander, it's likely they'll come face to face with something bigger, scarier, and more violent than them, so it's suggested that you never allow your dog to be more than 10 feet away from you.