Hi, if it's peace and quiet you are after then try the Niforos Apartments, at Petani Beach.
We stayed there in Sept 2004 and it was perfect, plus Petani Beach is one of the lesser known beaches and so very quiet too.
The family that onwed the place were so friendly, and made us feel at home the moment we arrived.
At the time we booked througn Tapestry Holidays, but I think they might take private bookings now.
Although to be honest most places in Kefalonia offer peace and tranquility, and definitely no lager louts.
Having said that I personally would not recommend the Skala area, as it was a bit too "Benidorm" for my liking.
Anyway, wherever you end up - enjoy, it's a beautiful island!