You can't get a torque wrench on those bolts. I do them by feel. Easiest thing is to practice on one of the bolts that is accessible, torque it down to the value needed for the interior bolt, the grab your end wrench and turn the bolt slightly. It might take a few times, but you can get pretty close that way.
If the manifold bolts are stubborn, soak them overnight with a good penetrating oil, I recommend Kroil or PB Blaster. Then warm the engine up and put on some gloves to remove the bolts.
