Originally Posted by chunky649

I have an upcoming business trip where I will arrive in FRA (Frankfurt) on a saturday morning. I've visited Frankfurt and area (Mainz, Heidleberg, etc) I don't have to be at work until late monday morning. So I decided I want to spend the weekend in Berlin. I will travel to Berlin on my own dime...

3 main questions:

What is the best (cost and time are large considerations) way to get from FRA to Berlin? I believe train is probably best, but the journey takes 5 hours?

I would like to stop in Cologne for a couple hours to visit the cathedral next to the train station. What is the best way to do this? The German db website is not easy to understand... Should I book 2 1-way tickets? or a "stop over" ticket? (I can't figure out the rules for "stopover"). Also, Is Cologne actually on the way? slightly out of the way? or really out of the way?

To complicate things, I am worried that my flight might come in late. In which case, the matter of changability and refundability comes into consideration. How much should i expect to pay if I pre-order my tickets and how much should I expect to pay on arrival of my flight?

Munich is another place I am thinking about, if that make more sense...