What about Neptune? There could be some lore mumbo jumbo turning the planet into an entire body of water instead of just ice. The reason I think Neptune would be an interesting idea is because of Kamino, from the Star Wars prequels. In the prequels, Obi Wan visits Kamino to investigate the rumors of a clone army. They could basically do something similar to this (minus the clone army) and have whole towns and villages on these platforms, which I think would be a real interesting setting.