With each aircraft, we normally provide sidewall panels to cover the side windows and ceiling panels, both of which have florescent lighting.  An air conditioning duct runs down the top center of the ceiling.  Air is drawn back into the air conditioning system through vents at the bottom of each sidewall panel.

The photo (left) has a wall framed up for a forward bathroom.  The bathroom wall in the photo has a pocket door that closes off the front of the fuselage.