Well, it can take anything from 3 to 4 hours, depending on the conditions. But if you are on a coach it will be a min. of 3 hours. The roads are very snowy and I was supprised that the coach didn't slip, but if you are travelling in the day you will find it a very steep climb, if at night you will be asleep! Oh, and look out for the packs of dogs in Sofia!