recess the doors and windows and leave all the rest 1/4" thick. I want to cut all the lines with a 1/16" straight bit doing down 1/16"
carve down the windows, door, and pediment. All other lines will be 1/16" End Mill.
After the windows are carved 1/16" down, I want to mill the mullion lines down to 1/8". All other lines are End Milled down 1/16".
Alternately, I will try milling the facade down around the windows and columns 1/16".
Alternately, if the window was re-drawn using closed geometry then it would be possible to cut it in layers so as to create a 3D effect w/ greater verisimilitude.
First, draw in some geometry so that the surrounding area may be cut away: