[masraum]

Assuming you have a long enough run, ridge vents are supposed to be the best (compared to a turbine). If you've got a hip roof, it seems to me that may severely limit the length of your ridge vent.

You may want to insulate the back of your access door. I did that with some of the foam sheet, and you could tell a difference afterward just walking under/past the door.

Do you have enough soffit venting for the ridge vent to keep up with? Has the soffit vent been blocked by insulation?

I think a powered vent, solar or otherwise would be a good option in certain environments.