The Outlaw Ocean https://www.amazon.com/Outlaw-Ocean-Journeys-Untamed-Frontie...
This is based on a series of articles the author wrote for the New York Times: https://www.nytimes.com/interactive/2015/07/24/world/the-out...
I had been under the impression that international waters were much more regulated. Man oh man, was I wrong.
Large national parks, western states, or open ocean: there are still a few places you can be hours from the nearest person, without cell service.
That doesn't mean the slots will be more than 80% payout, but there will be a payout to someone.
The Outlaw Sea: https://www.amazon.com/Outlaw-Sea-World-Freedom-Chaos/dp/086...
It's a pretty good look into the world of international sea travel as well. It even gets into the ship-breaking industry as well.