Here are a few suggestions for your next trip from Koszalin

In 4 hours, you can reach Posen.

In 5 hours, you can reach Berlin, Breslau.

In 6 hours, you can reach Warschau.

In 7 hours, you can reach Hamburg, Łódź.

In 8 hours, you can reach Krakau, Ostrava.

In 9 hours, you can reach Prag, München, Frankfurt am Main.

In 10+ hours, you can reach Paris, Budapest, Wien, Stockholm, Kopenhagen, Brüssel, Amsterdam, Vilnius, Bratislava, Zürich...