Wakamatsu Island is one of the five Goto Islands in the Nagasaki prefecture. In olden times many Christians moved to the islands to hide from persecution and many Christian churches have been built on the islands.
The Discover Japan tour Lupin mentions is a personal travel service started by Japan Railways in 1970, done to accommodate an increase in solo travelers. It's slogan was "Beautiful Japan & Me". It was reported to be quite successful.