Not so much.
Consider that, while the planets with the closest orbit to Earth are Mars and Venus, the planet which is actually closest to Earth on average is Mercury, because of its orbit, which brings it more often closer to Earth.
Ceres would be, on average, far away from any other destination in the solar system, which is terrible for a port. Something like going from Los Angeles to San Francisco through New York.
To be clear, I am not suggesting Mercury as better location, just giving it as an example on the need of considering the average distance, not just the distance between orbits.