The ships and trains only go between Johto and Kanto, and Pokemon are unable to fly or swim between regions, as they don't have enough stamina for it. In addition, where exactly would these other regions be? A blind expedition is not safe for you and your Pokemon.
text;
The ships and trains only go between Johto and Kanto, and Pokemon are unable to fly or swim between regions, as they don't have enough stamina for it. In addition, where exactly would these other regions be? A blind expedition is not safe for you and your Pokemon.
[And he knows all about flying blind, oh boy.]