Big diffuse lights

I have a scene with a long tall hallway (see attached) and it is lit primarily with tall area lights at each of the 3 courtyard-facing doors. I'm wondering if there are any additional tricks I can use to get it rendering quicker. There will be animated people milling about inside so I want to use BF.

At the moment, at 1920x1080 on SR's "Very Good" setting, it takes over 3 hours per frame.

Thank you.

Just sent you an e-mail.