I guess it didn't fit with the goal of 'walking' around the world, probably wanted to avoid motorised transport

> At the start of his quest, Bushby made two rules for himself, neither of which he has broken.

> “I can’t use transport to advance, and I can’t go home until I arrive on foot,” Bushby said. “If I get stuck somewhere, I have to figure it out.”

The only ferry in the Caspian I know goes to Turkmenistan, which is North Korea-level strict with issuing visas.