We will be in Bergen during the Bergenfest but won't be going to the concerts. From the Bergenfest website it appears that we will still be able to go to the Rosenkrantz Tower and Hakon's Hall of the fortress. Is that true? Below is what the website says. I am unclear about who they are referring to as guests--guests for the concerts or guests to the city.
"Bergenfest has a special responsibility to take care of its festival grounds, as Bergenhus Festning is a cultural heritage site. All protected areas will be closed off during the festival. However, we reccommend all guests to pay the neighboring Håkonshallen and Rosenkranztårnet a visit."
The concerts take place in a large green space behind the fortress and separate from it. People going to the concerts will enter via a gap in the wall on the back side while the entrance to the tower and hall are on the side facing the town.