If you’re only there for 1–2 weeks i wouldnt recommend the interrail pass, as you wont have enough time to be travelling outside of the central europe area (if youre leaving from frankfurt wien or praha anyway.
You would be fine to just by a few books and go and explore the cities. The great thing about Europe is that you couldn’t possibly miss the incredible architecture and restaurants etc.
In Praha, do not buy ANYTHING on the main tourist strip near the George bridge or whatever it is. Here a pint of beer is £2.50
If you walk literally 150yd down away from the tourist buzz, you will find cafés and bars with beer for 50p (was like that about 3 years ago, anyway)
I don’t know why you would go to Austria to learn German, it’s like going to Scotland to learn English, but OK. Wien is another place so full of great architecture and café culture, you won’t be stuck for things to do.
I love Frankfurt. I will recommend taking a boat for a ride on the river, maybe down to the Rhine (it joins). You can just walk up and buy a ticket, they are very regular. If you want, pick one where you can get off in a smaller town down river and take a walk up the banks of the Rhine. They are covered with vineyards, and once you get to the top you will be ready to sit down and enjoy a glass of wine, whilst soaking up the fantastic views over the valley. Then hop on back to Frankfurt and wander round for a few hours. There are plenty of shops and nice architecture and places to stop for a drink or some food.
Frankfurt pic
Frankfurt pic
Make sure you get yesen down south of the river to Sachsenhausen. There are so many great independent eateries and breweries. I wish I could remember the name of the place I went, everyone sat in this huge courtyard in the middle of a leaning old wattle and daub building, they served the most fantastic Wurst und Sauerkraut, there must have been a pound and a half of meat/black pudding there and it went perfectly with the pickled cabbage….
Sachsenhausen pic1
Sachsenhausen pic2
(These are pretty minor side roads, maybe representing about 0.5% of the area, and it is usually pretty busy between lunch and late)
OK I couldnt elaborate enough on how much great things there are to see and eat and drink in the West German cities (I haven’t been to the East yet), but rest assured that almost any town you find yourself in is going to be beautiful and exciting. I can personally recommend that, in Hamburg, Koln, Frankfurt and all the towns and cities in between, all along the Rhineland, you will never be at a loss for what to do. You can really just buy a day public transit pass (and public transit there is great) and explore. The city-centres are the safest areas in Europe, not like America at all.