This video shows how to manipulate gravity blocks to use as lifters and fast transportation within large ships and bases. The system works with a combination of gravity blocks, docking modules, and docked ships. It is a lot easier to explain in the video, so I will leave the link with you.
http://www.youtube.com/watch?v=nZZ_DrnNWC0
http://www.youtube.com/watch?v=nZZ_DrnNWC0