I would say it is about at 30 minute drive, all along the river though so its a nice pituresque journey. Would definitly suggest eating in samokov or beli iskar as Govadartsi is a bit limited.
We have a lot who come into the restaurant who say how nice it is not to be in borovets so a little drive isn't much to worry about!
Get a half day lift pass for the afternoon- cheaper and 41/5 hours skiing is enough for most!