Me and my family went one summer for three weeks and then back again the next smmer for another three weeks...
(the first year was pretty much the last year that they still had all border stops, got a ton of cool stamps in my passport, none the second year )
I still want to go again to see everything.
When we went, we only went to small towns because we wanted to see the culture. A good book to get is call (I think) Europe Through the Backdoor. Had great advice on places to see and go and how to get around.
No one in our party spoke any native languages but we had a couple of pocket translation books and I think that we noticed that when the local people even in small towns, saw us trying to speak their language and not being dirty Americans, they were very helpful and would look for words they didn't know in our book and show us what they were trying to say. Make sure you get the translation books that have from English to another, and the other way too. I think that the reason for people here saying bad things about people being rude or what not is because the EXPECT people in other contries to speak English, and think they are rude when they don't.
I'll never forget my time there, absolutely amazing, nothing like it in America.