The chimney does go most of the way down to the floor of the firebox. I don't remember exactly how far without taking a tape measure, but it is roughly 6 or 7" off the floor of the firebox I think. I didn't take pictures of the building of the door itself, but what I did was take a piece of 3/8 and cut it with a torch to match my opening, then welded some round-nose angle around the outside of it to overlap the door frame, and this gap is where my rope gasket sits. As for the fire brick, I laid my door down flat on my work bench and built a frame out of some 1/8" flat metal I had laying around. I basically stacked the firebricks on the door the way I wanted, then marked the outline of them with soapstone and built a frame off those dimensions. Then, I welded a few places around the frame to hold it to the door and inserted the firebricks, then laid expanded metal down across the top and tacked it all around to hold the bricks in place. I did not use any adhesive to hold them if that was what you were referring to. I shot a few photos if that helps any. Don't laugh at my door latch and hinges--I've never had a shop class, so everything I fabbed was cut out with the torch and looks pretty rudimentary, but at least it works.
My father-in-law helped with the water-tight welding of the tanks, but the door and everything else I've tried to do on my own. Needless to say, his work is much prettier than mine.