Most of Arcadia's land was populated by human cities and civilization, but the Wild Zones weren't small either. To a certain extent, beasts were just as necessary as animals were, so their existence had to be tolerated.
There were large parts of the world that had been properly designated as Wild Zones. These Wild Zones were then further divided so one could see exactly what level of beast lived where.
However, even through the Wild Zones, human infrastructure was present. Roads and trade lines existed even in beast-heavy environments.
That wasn't to say these routes were safe. One absolutely still risked the chance of being attacked by crossing them. Still, it was only a matter of taking the right precautions. The more important fact was that humans could maintain such routes without being pushed back by beasts.