Do a Guidebook specifically about the volcano. Internet search engines will show Airbnb Listings Because Airbnb website has a good audience. For them to show you they have to pick up keywords and volcano lodging is a sought after item.
The best advertising vehicle in Hawaii is locals. They truly appreciated what you accomplished. And as you know anybody from the mainland vacationing in Hawaii that talked to you once 10 years ago will call you for recommendations of where to stay and what to see.