Why go that far? Titan, Saturn's moon, is loaded with far more hydrocarbons than are available on Earth.
How did we discover (and begin actually using) the Americas? Christopher Columbus was sent on a trip to retrieve resources from India. It was a financial trip, supposed to enrich the government, not an exploratory one.
That's kind of how it's always been. Societies have discovered new people, lands, and resources by accident while trying to expand their empires (generally).
Furthermore, as we continue to consume resources and grow our population, we should probably strive to expand our society to other locations before we overconsume and overpopulate to the point that it starts to cause problems.