I think they were quite fuzzy originally.Interesting to speculate how much further along space exploration might have been had the US government not felt emasculated at the USSR having the first man in space and NASA not had to put all of their eggs into the basket of getting a man to the moon before the decade was out. Of course, the case could be made that if Kennedy weren't assassinated and the remainder of his first and any second term not gone very well that the promise would have been quietly forgotten amongst a myriad of other issues piling up.
What were NASA's timescales for their original plan? An orbiting laboratory by 1970? A space station by 1975? A lunar orbit by 1980? A moon landing by 1990? Mars by the Millennium?