My husband and I are planning a trip to Germany/Poland to go see one of our favorite bands. The band will be playing almost consecutive days in 4 different cities. Munich on October 24th, Frankfurt on October 25th, Berlin on October 27th, and Gdansk on October 28th. We've been to Munich and Gdansk before, so I am fine on booking hotels, etc.
I know that we can get between these cities pretty easily by train. Any suggestions on buying train tickets? Is there some sort of pass that I could get that would be cheaper than buying tickets individually?