Here are a few suggestions for your next trip from Dobre Miasto
In 5 hours, you can reach Warsaw, Gdańsk, Bydgoszcz, Gdynia.
In 6 hours, you can reach Poznań, Białystok.
In 7 hours, you can reach Łódź, Lublin, Częstochowa.
In 8 hours, you can reach Kraków, Wrocław, Szczecin, Katowice, Sosnowiec.
Book - Trainline
Book - SNCF Connect
Book - Deutsche Bahn