In reply to Doug:
Expect rain, wind, snow as worst, beatuful autumn sunshine as best. You can be sure in sub zero nights. Watch out forecast, Fagaras can be surprizingly cruel. Fog could be also dangerous, easy to lost. Go in five or six person group and talk aloud in the forest foothills against the bears. Against sheperd dogs form a hedgehog stance with walking poles and shout for the sheperds. Sheperds be happy if you can treat them with some cigarettes, bring some even if you do not smoke. Thiefs are occasinally a real problem. Keep everthing behind the same ziplock where you sleep, mostly your boots!
Best section is between Lake Avrig and Peak Moldoveanu. From Sibiu to reach the main ridge requets a whole day. Try to catch a taxi to the last villiges but will have a half day trek from there.
At the end, it is one of the best one week long ridge trek in Europe.