I just imagined it as a big round version of O’Neill’s cylinders but with the sea floating there in the middle...
that would be a sight
The Fifties version envisioned Ceres being spun up to provide the centrifugal force for artificial gravity. Spaces were to be dug out in multiple levels with the ceilings a few thousand feet high. The ceilings are high enough for the atmospheric diffusion to make the overhead appear to be a blue sky. The levels were stacked towards the core of the asteroid. Zero gravity spaceship ports were located at the poles of rotation. Industrial facilities were located in some cases as satellites habitats for Ceres.