People
Somewhere not too far from here, toward the middle of the island, there may have been heaven on earth, but hell had certainly set up business on its porch.
— Douglas Adams · Last Chance To See

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Paradise may exist somewhere in the island's middle, the speaker allows, but hell has opened a shop right on the front porch. It's a funny metaphor for a place that's supposedly beautiful yet hostile to reach, with the awful part greeting you first.
Context reviewed