I'd 1st of all use ranged fall-off on lights. After a certain distance lights from small houses don't matter for the rest of the scene (especially if theres no indirect light, like any bryce scene that doesnt use TA). It'll possibly save u lotsa time. Also volumetric light effects would be more efficiently done in post.
I'd also turn of TIR, prolly no use for it in this scene, and maybe check out if u can limit reflective surfaces. Raydepth can be kept low if theres no prominent reflective or refractive elements in the scene also.
And if ur rendering for 300dpi, theres no use for insane AA settings either, so dont let urself get swept away with those either. Normal AA is prolly gunna do just fine.

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