I think we know much of what we need to know (the basics: how to procreate, how to create a craft, etc; plus the steps to take) but the costs are just a little hard to justify for many given existing world problems and a predilection to just fighting everything.

No, not exactly. We still dont know if we are able to give healthy births with no or less gravitation.

Reproduction doesn't address the aging problem at all. To quote Woody Allen, "I don't want to achieve immortality through my work. I want to achieve immortality by not dying.". The same thing applies to reproduction: I don't want to achieve "immortality" of some fraction of my genetic code, I want to achieve immortality by not dying. :)

He looks crazy, with the enormous beard, but his appearance belies an impressive amount of sanity.

I've been really impressed by listening to him. In particular, he's very up-front about what we don't know yet, and the uncertainty involved, and he's very careful not to promise more than he can scientifically justify. This sort of thing does not come through very well in sensationalist mass-media portrayals of him, though.

I think he has a good chance of finding ways to slow down the aging process and buy us some time, just like we've managed to extend lifespans heavily through other advances in medical and related technology. However, I have very low confidence that that direction of research will manage to completely solve the problem. We have far too many ways of breaking down, and not all of them seem solvable by patching. I have somewhat more hope for a solution from the AI camp, personally. I just hope the Uncomfortable Truths Well (http://xkcd.com/568/) doesn't prove correct.