I believe that the best way to get to the stars is by working together freely, via voluntary co-operation or a private business, and not by a government bureaucracy (no more wildly overpriced space shuttles!)
My main inspiration is from this article, on students working together to build benches for buses. The Detroit government hates it, of course, but it’s far too bankrupt and lazy to do a thing about it. In the meantime, the students are openly ignoring the bleatings of the bureaucrats, and doing what they need to do to care for the oldsters.
This is what life is all about: initiative, love, imagination, hard work, and brushing away evil like the petty triviality it was always destined to be.
While 3D printing, agelessness and very cheap energy is on its way, I don’t think that I will live to see it. But if there is any possibility of FTL travel (doubtful) for STL travel, then the kind of power tech we will have in 2220 or so will make some kind of STL travel possible.
A century of advances before we have the power we need, at the current rate of technological advancement? Should be plenty. By 2300, a private, DYI project by a few hundred volunteers should be able to pick out a starsystem, map it out, and terraform it. By that time, the main cost is going to be time and risk, not money or material or R&D.
(I personally don’t believe that Faster-than-Light travel is possible, as FTL travel implies time travel, and casualty – time’s arrow only pointing one way – is critical to the administration of justice, divine or otherwise.)