Inter-domain travel was a troublesome matter, and when Tower of Truth was first built, the issue of regional divisions had been considered; largely uninhabited areas were almost always on the edges of the Tower of Truth's territories.
Although this made each territory of the Tower of Truth approximately the same size, it also made communication between the Towers much more difficult.
Generally speaking, to travel across uninhabited areas for inter-domain travel, one needed at least the strength of a Three Rings Wizard.
And even with a Three Rings Wizard, passing through uninhabited areas was not entirely safe. Many Three Rings Wizards had perished in these areas during their travels.
But this was only when wizards traveled on their own.
If a wizard was willing to spend money or had acquaintances in the Wizard Commerce, he could completely travel through inter-domain routes managed by the Wizard Commerce.
And that was precisely the purpose of Richard's journey.
