User blog comment:AYET/Mihawk - to the NW and back.../@comment-3425840-20120220143723

The thing that intrigues me the most is, how the hell could he go back from Baratie to Shanks with Luffy's poster in such a short time (the time he showed the poster to shanks was not much after the Baratie incident).

Back to the main topic, as he is a Shichibukai he can go through Mariejoa no problem and even if that is close, he an go through FI cause he is very powerful and just put his sword hand out of the bubble and make anyone who dares to attack him mince meat.

Finally, he can use calm belt to travel as he probably is strong enough to slice up any Seaking that is foolish enough to attack him into fine pieces.