I have begun a significantly large project based on Vincent Callebaut's work "LILYPAD, A FLOATING ECOPOLIS FOR CLIMATE REFUGEES". This has featured in many scientific and futurology publications but most people remember it as "that floating city". Bascially the concept is a floating city (on water not air) which has everything a normal city has but compacted into a single circular floating platform. The platform has translated into 301 blocks diameter, which is pretty huge. This is projected up from the water's surface up 20 blocks and then three large structures sprout from the top.
(All this can be seen from the pictures on the following website).

http://vincent.callebaut.org/planche-lilypad_pl32.htmll

The problem is I have no idea how to do the interior design. Basically I need to fill up the three structures with everything normally found in a city.
The three structures are to be 50-70 in width (curved to follow the circles shape) and are 80, 100 and 120 in height respectively.

Any input would be most appreciated as I have it a creative wall filling up the huge amount of space I have to play with.