Although Giant Ghost City wasn't extremely far away from Arch-Emperor City, it still took Duke Deathcrier months of work to get them close.
And he was a deva. If Bai Xiaochun had been piloting the ship alone, the spiritual power wastage would have been immense. Even by replenishing himself with soul medicine, it would have been difficult to keep going for very long. Most importantly of all, he would have faced ten times the amount of danger.
Whether it was the bizarre creatures that inhabited the Wildlands, or the hordes of souls with their profound death auras, they were all things that left Bai Xiaochun trembling in fear. Of course, the souls would have been easier for him to deal with, but as for the beasts, they were shocking to the extreme.
At one point along the way, he saw a towering tree that was so shriveled it looked dead. However, it could move, and would consume anything that got too close to it.