The San Juan islands that are not among the four served by the ferry. Life is different. You have three options: Operate your own boat, or “charter” a trip on the Paraclete - much more expensive than the ferry and irregular service - or, on a few islands, fly your own airplane!
It is another world on these islands. Being hard to access, they are very quiet. I remember when staying at Camp Orkila on Orcas Island and looking across the water to Waldron Island. And being amazed that I was seeing lights. How do they have electricity? By generator. Of course lighting can also be by propane. Wow.
Illogically the author includes Guemes Island. It’s not among the main San Juan Islands, being very close to Anacortes. But the problem is, it does have a ferry. It’s not Washington State, but it’s public, reasonably priced and operates throughout the day, seven days a week - Skagit County owned and operated.