This is the plan for adding the new room off the reading room, plus adding a 13'x16' room in the open center area. A hallway will give access to the two new rooms and the back door. The reading room loses its window in this design as there's no point putting a window on the outside wall as it just looks into the brick wall of the house next door. The three windows at the back of the living room are moved to the back of the new center room.  I forgot to add 3 skylights to give light to the living room - you can see them in the design for the big room.  The only tricky thing will be lining up the new roof over the new center room with the existing rooflines on the left, front and right side and maintain building code as to minimum angle. The existing deck can be rebuilt to use the 6 foot setback from the new room on the right.