The distance is really hard for me to really understand. Currently the fastest manned vehicle we have has been capable of about 17,000 mph. At that speed it would take right around a 855600 years to reach 667CC. I'm sure we'll wait for better technology before attempting that kind of trip.

Non-carbon based lifeforms - definitely hypothetically possible. Unfortunately we don't currently have evidence of lifeforms using anything but carbon biochemistry. My personal belief is it is absolutely possible. Silicon has quite a few similarities to carbon and that's just an example of life having an analogous biochemistry. Who knows what's possible with the diversity that could be experienced in different environments?