Like Rhia, I spent part of a snowy day playing with the Victorian Gift Shop and optimizing for SuperFly.  But unlike Rhia's render, I kept the ceiling intact because exposing the room to outside lighting looks unnatural.  BTW Rhia, I like your render version of the room.  My approach, rework the textures for SuperFly.  Add a little noise to the walls and connect everything to the PhysicalSurface node.  As for the lights with the set, there are only 4 actual lights available,  the other lamps all have ambient mesh and have one set of textures.  Easier to address with a single set of shaders. I deleted almost all the actual lights because they were placed outside the room and were of no benefit to the render.  I did keep an area light that was relocated to the inside of the room and placed at ceiling level.  As for the background image, just a jpeg imported into the background was rescaled and moved into position.  I found that the SuprFly glass offered with Poser is all wrong, it magnifies the image when viewed through the window.  That had to be modified so that it looks like a pane of glass rather than a bottle.  Render settings and render below.