I would suggest that a principal theme of "Roadways" is the insufficiency of the "ordinary" life. Man seeks something beyond the roads that lead to known places, of which London and Wales are symbolic in the opening stanza. The speaker yearns for the sea, not for the things at home:
Most roads lead men homewards,
My road leads me forth.
An interesting parallel exists between the tone of "Roadways" and the idea expressed on the opening page of Melville's Moby Dick. Ishmael indicates that whenever he is seized by "hypo" (a nineteenth-century term for depression) his solution is to go to sea. Masefield similarly has the speaker in "Roadways" say that the things one encounters on dry land—earth's "road dust," for instance—are what must be avoided if one is to have a meaningful life. In what is perhaps his most famous poem, "Sea Fever," he states:
...all I ask is a tall ship, and a star to steer her by.
In "Roadways" he seeks "that one beauty God put me here to find." What this suggests, in my view, is that it is only by "going forth," rather than by accepting the ordinary, earth-bound life, that man finds value and fulfillment. The sea represents not only the opposite of the ordinariness of dry land, but danger. The "bronzed sailors" to whom the speaker alludes are those who have gained glory by exposing themselves to the perils of the sea. In Masefield's view, the choice is between living without, or living with, such perils, and he chooses the latter.