I presume he meant elected directly from VP to president (as the conversation was become VP in 2012 and run for President in 2016).
So you exclude Tyler (lol, didn't realise he was later elected to the Confederate Congress), Fillmore, Andrew Johnson, Arthur, Teddy Roosevelt, Coolidge, Truman, Lyndon Johnson, and Ford who attained presidency on the death or resignation of the President rather than through an election, though 4 of 9 were later elected to another term.
Nixon lost one election and sat out a second between his Vice Presidency and Presidency.
By excluding those never elected VP wins 9 to 6 by my count, removing those elected only after becoming president it is 6 to 5 for Secretary of State and directly jumping into presidency through an election is 4-3 for VP. More importantly, the last Secretary of State elected to the Presidency was 1825, while the last former Secretary of State was 1857 (and the other two of them were VP immediately before President). While you have H W Bush and Nixon within the past century being VP before President both positions were more common to become president in the 19th century.
There is no real reason for Hillary to want to be VP as a jumping off point for President unless she expects Obama to die or resign before 2016. Is she wants the job it is more likely she gave up on being President and decided to settle for first female Vice President. That is if she pushes for the job, I doubt she would object to it if it just fell into her lap.