Very interesting article!
I think that the concept of folding space may end up being the best way to jump across the vast distances in this galaxy. Of course, at this point in time, no one has any idea of how to fold space, and I think most people think it's impossible, but folding space between large gravity wells is a concept worth applying serious thought to. It will require a much deeper understanding of gravity than humans now possess, and energy sources that are still theoretical.