Hi, I haven't been to Budapest nor Oslo. In Prague, besides main sights, you should visit a district that's cross the river from the castle - there are some nice pubs. Try "Kozel" black beer. If you're into musical subcultures, you should visit "Cross club", try google for directions and info. If you have time, go to Cracow, old capital of Poland - it's not far. You also might try Vilnius (Lithuania), or Vienna (Austria, very nice) but that's further away. Many people in Eastern and Central Europe, even mid-aged, easily speak English, no problems. Godspeed.