Zeus, like so many Gods, goes on adventures in our myths. His adventures often include some poor virgin princess from somewhere that will be hounded by Hera at some point, but this is not always the case. Zeus travels, often making himself into a soldier, a king, a general, or some beast or other.
On one such journey, he and Hermes wander the world in search of good people. He seeks, but does not find, upstanding people who uphold the holy laws of the Gods, laws which are different from our own today, but which often resonate. Hospitality was a sacred law among the ancient people of the Mediterranean, and Zeus was, as were many Gods of that region who could, possibly, be identified with him, a God of Hosts.
Unlike in our modern world, it was considered a breach of divine law to, essentially, be a bad host. The law broken in Sodom was not homosexuality, but a breach of hospitality, for YHWH was the Hebrew God of Hosts, and to deny someone shelter was seen as the sign of an immoral person. The story of the birth of Jesus, for example, shows us a place, Bethlehem, in which people had become isolated and selfish, denying Mary a place though she was in great need. You are not shown this simply as a way to show you her suffering, but to show you that the world she lived in had become "evil" by turning its back on this divine law.
In the story of the Birth of Apollo, Leto is denied a place to give birth. She has, at this point already given birth to Artemis, who is with her and now must help her give birth to Apollo on Delos, the only island that will have her. Again, the Goddess and her two divine children would grant this island great honor and make it sacred, for they upheld the divine law.
Zeus, the God of Hosts holds us to this, that in one way or another, we must, in essence, help each other. Shelters and homes are not just sacred to Hestia, but to Zeus as well, for his is the will, the power, the divine law that requires us to offer aid to those in need, shelter to those traveling through our cities.
One might argue, of course, that this is not something we can do today, and I suppose in much of the civilized world this is true. Our cities are so vast, the numbers of people so large, that it becomes impossible. But we can help by making sure that shelter and inviting hospitality is available. That we do to assure that the homeless are housed, the sick cared for, and those in need, for whatever reason, have somewhere to turn.
But Zeus as Traveller is also a watcher of men. He is here with us, everywhere we are, watching as we do unto each other that which we would never want done to us. He is the conduit to Olympus, he who regulates the divine powers, and perhaps, he who assures that divine gifts are not handed out to the worst among us.
But let me remove myself from all of that and get to the term Traveller itself. For most of us who follow a path under the Shadow of mighty Olympus, the God of Travelers is clearly Hermes, and this does not change that. Hermes is he who travels between the worlds, the messenger, the guide, but it is a mistake to assume that the universe is cut up into neat little departments and then assigned to particular gods and only to them. Were that the case, the Gods would be such simple things. Zeus, the king, the lord of hosts, husband, father, thunderstorms. Boom, done!
But, alas, no such luck for us.
No, Gods receive titles and attributes from man, because we see them in different ways, we receive their blessings in different ways, and we seek them out in different ways. Zeus, the King of the Gods, is one who was worshipped all over the Greek world, and beyond by many names and in many forms, and as he made his way, he touched upon the religions, the cults, the myths of many people, each one imprinting upon his legend a slightly different form, for when he came, he left behind something new in his wake, as he travelled, he spread divine law and justice, among these that greatest of divine laws, hospitality.
