Starting on the air plenum was a little premature. I finalized all of the lighting wire runs except for the switch plate back lighting prior to this post.
Back light fabrication consists of first a shroud to attach the lights to, then adhere the lights, mount the shroud with wire routing etc. Then wire everything up.
The only set of lights I am not sure how I want to mount is the overhead. I would like to recess them in some way, but can't do it the same way as the floor light due to the length of the strip lights. Surface mounting will not give me the effect I am after.