For our next trip to Germany, we are thinking about renting an auto in Frankfurt and driving the Romantische Straße and also visiting Bamberg. We will end up in Füssen, but stay in Berchtesgaden. My question is - what is the norm on the methods for paying for petrol along the way - should I assume I will need to pay in cash most of the time? How common are pumps that accept, say, VISA?
I do not anticipate driving the Autobahn much, if any, so I am guessing that Tankstellen along the local roads will require cash?