The world is one that operates in a similar fashion to that of YKK (without the apocalypse, though), and provides the characters with a huge amount of freedom.
As expected of Ashinano, the story is quite relaxing, but spices it all up by being far more focused on wanderlust than YKK was. This world has just as many tantalizing unsolved mysteries as the one Alpha lives in; that's an aspect of storytelling I've seen in precious few stories (Blame, Dark Souls, YKK, and Name of the Wind), and it's something I think adds an enormou sense of Life to any given artistic work.
Including ambiguous details allows the world to exist beyond the bounds of its narrative, and keep the mind forever wondering what else exists. I think this really touches at a part of the human mind that is not usually accessible to the average person. The world has become small, but in stories like these we can feel what it must have felt like to be at the edge of the known world.
Ashinano panels this story in such a way as to convey the vastness of a world ten times larger than our own, and to allow us to feel the slow and steady flight of the Cub plane.
An interesting note, this story was the first I've ever read that genuinely brought tears to my eyes from a page transition. The moment Isaki sees the vision atop Mount Fuji is one I'll never forget. I was blown away by the buildup and payoff Ashinano provided with this adventure.
For anyone enamored with stories about exploration and pushing one's boundaries, this is an absolute must read.
