The main difference between the groups of planets in our solar system lies in their composition and characteristics. The planets closest to the Sun (the terrestrial planets: Mercury, Venus, Earth, and Mars) have rocky surfaces and are primarily composed of rocks and metals. In contrast, the planets farthest from the Sun (the gas giants: Jupiter and Saturn, and the ice giants: Uranus and Neptune) are predominantly composed of gases and ices, making them much larger and not solid like the terrestrial planets.
The statement about planets farthest from the Sun traveling outside their own orbits is not accurate; all planets in the solar system follow their own distinct orbital paths around the Sun. Therefore, the primary distinction is indeed based on their rocky versus gaseous composition, rather than any difference in their orbital behavior.