Pronunciation of "Vier uur"
Are the words connected? Is it better to speak out the "r" like it were just one word "vieruur"?

Question

Answer

No, definitely two words. Like Kevin says, pretty much the same as in German (though not completely the same). These might be useful:

http://en.wiktionary.org/wiki/vier#Pronunciation
http://en.wiktionary.org/wiki/uur#Pronunciation

Answer

Nope, it's similar to the german "vier uhr".  The vier is pronounced exactly as in german. "vier üüüüüür". two words, 2 syllables