Brúnastaðir from Sauðárkrókur.
You go through Sauðárkrókur east, and then take the Road 76 to Siglufjordur. You drive that road for a while, past the little village Hofsos. Ca 25 km north of Hofsos, you turn left as if you are going to Siglufjörður, then you see Brúnastaðir farm, a sign to the left.

How to get from Akureyri to Brúnastaðir
If you are coming from the eastern part of Iceland, or from Akureyri, to us, this is the easisest way is to take the road that goes through Siglufjörður. It is 22 km drive to Brúnastaðir from Siglufjörður