There's a good to fair chance Hillary will lose Iowa and New Hampshire, since both states are demographically perfect for someone like Sanders, but her campaign has built up an enormous organisation in the South to take the black votes and win the heavily populated Southern conservative states, the same strategy that won Obama the 08 nomination despite her getting the most votes. It's a numbers game at this point and unless there's an indictment from the FBI over the email business, I don't see her losing. Biden might pose a credible threat if he decides to jump in but party elites have by and large rallied around Hillary, as the endorsements so far show.
So that leaves the Gen.Election. Very scary looking at the polls right now but again, we have to remember this whole thing is barely even getting out of the block. If, by miracles (or the most comically sordid luck imaginable), the Trumpster wins the Rep. nomination, short of killing babies and eating them, Hillary will sail to the White House without even breaking a sweat. The GOP establishment doesn't want that to happen, of course, so the end game for them will probably be Bush or Rubio as the nominee + Kasich as VP pick to carry Florida and Ohio. However, with the crazy teabaggers screaming for attention, it's more likely they will have to include an outsider candidate as VP, and in that scenario, that may as well be a woman to counter the Dems on women' votes. So, Bush/Rubio+ Fiorina. The problem is there is just as much baggage with this lot as it is with Hillary, so there won't be a shortage of ammunition for the Dems to work with. It'll be a very long negative campaign from both sides, with neither coming out looking any good, but I still expect the Dems to win, if only because the electoral map has swung heavily in their favour during the last 10 years.
The more interesting race in 2016 will be in the Senate. Minimum of 9 and up to 13 seats may be changed. If the Dems win the presidency AND majority in the Senate, then the world just might be spared another Middle East clusterfeck, and with up to 3 SCOTUS nominations in the next 8 years, it's imperative there's a liberal president in the White House. 2 more conservative judges can undo years of effort and progress in socially contentious issues.