Out of curiosity - are you planning on having an outside view from windows that would require you to actually create a landscape and deal with that, or is this just all interiors with no views?
aside from the obvious fact that for perfomance sake the views can be faked with images - if you want to add that extra layer of complexity at all…
I recently ran several tests with pie, vr, a gtx 160 ti, and around 2k static meshes that were being procedurally added in (with 10 different materials).
The performance drop wasnt really too bad - or mybe i just expected much worse.