As far as the ceiling ventilation system goes, I'm going to follow Bonnie's lead and make a cardboard ductwork, then from there I'll decide whether to go to paneling or to just poly the cardboard.
in the mean time I wanted to get some things out of the way.
first thing was the window framing.
:-)
(CLICK ON PICTURE TO EXPAND)
Note the red stained, chip board behind the paneling. What you will see on the right side is indicative of the other 3 sides. (yes, that's 12v wiring all over the place.)


I was surprised at how "untrue" the chip board was from the original builder. So I sanded it true. Where the red is missing is what got sanded. (I did not restain.)


I had 3 pieces of 1/4 round and I liked this one the best. :-) I did shim the paneling some in spots to level it with the trim.


so window is trimmed, first phase.
I am considering one other piece of trim, a 1" x 1/4" trim piece on the paneling face to frame it, once more.
final phase for that is the window dressing.
options include drapes, pull down ratchet blind, horizontal blinds.
I think I'll go with the drapes and horizontal blinds...
Ceiling goes in first, so I can put the window dressing hardware safely in the "wall meets ceiling" corner, out of the way.
I am planning on putting as much interior hardware as I can in the corners to keep from "braining" myself on them, or at least minimizing the damage to me.