Cosmography

The Solar System comprises:

the Sun;
four inner planets, including the Earth-Moon double planet;
the asteroid belt;
four outer planets;
the Kuiper Belt;
the Oort Cloud.

In Robert Heinlein's Future History, the Moon and two inner planets, Mars and Venus, are colonized;

in Larry Niven's Known Space future history, the Moon and the asteroid belt are colonized, the Belt becomes politically independent of the UN Earth-Moon government and a human protector hides in the cometary halo;

in Poul Anderson's History of Technic Civilization, two different extrasolar species are allowed to colonize Mars and the outer planet, Jupiter, respectively;

in Anderson's Harvest of Stars future history, Lunarians adapted to live in lunar gravity colonize the Moon and later Proserpina in the Kuiper Belt, from where they mine the comets of the Oort Cloud, and both Terrans and Lunarians colonize Mars;

the Oort Cloud "...mingled with the comet clouds of neighbor suns..." (The Fleet Of Stars, p. 38);

the nearest other star, Proxima Centauri, forms a triple system with Alpha Centauri A and B;

Lunarians have colonized asteroids of Alpha Centauri A whereas Terrans who colonized a doomed planet in that system have moved to systems further away.