Dave Bonta's short poem is about the small freedoms of a private, makeshift space. The speaker seems to be a man who retreats to a shed, and the poem suggests that this place gives him something an ordinary room can't. "A room is half as good as a shed" is a playful, slightly stubborn claim, the kind of thing someone says when they've made up their mind about where they belong.
The opening image is the most striking one: "the little map of the hand." The palm, with its creased lines, becomes a landscape to travel across, so the going-places happens in the imagination or through touch and work, not on a long journey. The shed seems to be where that happens.
The last lines, "I get out / with my song," feel light and relieved. The mood is quiet, content and a little mischievous. The speaker finds escape and voice in a small, humble place, and the poem's brevity matches that modest happiness.