Some people don't cut and hang dry, they slow dry in the pot. It's more of a bitch to trim, but it'll give your plants as much time as possible to finish. By the looks of it, you need another 10 days or so. Maybe two weeks.
So give them one last really good watering right before you leave. You can keep the lights on the timer. When you get back, they'll have had another week to grow and will be in the process of a slow, slow dry. Keep the air circulating to prevent mold, and keep the odor control going!
Good luck!
PS - if you fear fire, then just put the pots out in a room. There will be some light cycle due to the normal light coming through the windows. Keep the air circulating as stated above.