Well: Dwelling On Slope

the completion of this image marks the start of the whole Well City Project, Which the Dim Container Project belong to.
The Chinese character “井” means water well in English, it also have the geometric shape of road blocks, which may be refered to as a graphical representation of the city.
This is one of the district in Well City, the image is showing a slop area multipurpose dwelling section, whose parts are mostly containers.
There's a elementary school on the left, some grocery shops on the first floor compartments.
And there's also a cable transport system above, providing container transport service, there's also a ground-based train station on the right bottom of the image.

I spent nearly two days render this, any way I can speed up such things? (format A4*2)

Comments and Suggestions are gladly welcomed!!!