Copy/paste from an earlier post:
Koprivhstitsa, a lovely little village 100km east of Sophia, don´t expect luxury hotels but there are cheap places (formost B&B´s) with character to stay. Worth spending a night. Train is slow so it need a few hours to get there from Sophia. Have a look in a Lonely Planet guide for more info.
The Bulgarian National Historical Museum (if I remember well better known as “Rezidentsia Boyana”) 10km south-west of Sophia is certainly worth a visit. I used a taxi to get there.
If I remember well (visit 2007) a good place in Sophia for a typical Bulgarian dinner and life music is “Pri Yafata” next to the Thracia Hotel.