Road-to-Ferry Ratio

Here's a fine view for passengers approaching Papa Stour, Shetland, from the ferry. This could be the island with the lowest road mileage that has the services of a regular vehicular ferry. The waiting room (below)

is adjacent to the ferry terminal, which is about a mile from the air-strip (below) where the road ends.

Of course there are occasions when agricultural machinery is conveyed from West Burrafirth, on Mainland Shetland, to work the island's extensive fields, but there is virtually no network of metalled roads to provide routes for cars. There are some spurs to crofts adding, perhaps, another mile. Can anyone propose a lower ratio of, say, 2:1 on another Scottish island?

Scottish Islands Explorer - also a low ratio of readers here