Instead of a bunch of planets through space, I would make the entire universe an endless plain, with rivers, mountains, and all manner of terrain. Light and weather would be fixed, areas that had light would always have light, areas with darkness would stay with darkness, same with weather. Then plonk humans and fauna and watch my own little MMORPG world begin. Occasionally I would launch massive armies of Timurids to periodically invade the place, because I am not nice.