Unless Hillary's campaign completely fails in all three of the following points, I think Hillary will win by anywhere from Obama's 2012 victory margin to an epic landslide:
1) Ensure the convention goes smoothly and unites the party. Offer as many concessions to Sanders and his delegates as they need to keep relatively quiet. If she and the DNC are successful in this regard, her favorables will probably rise into the mid-forties.
2) Launch a multi-front scorched earth campaign that ensures the visceral negative feelings Trump provokes within ~50% of the voting electorate remain that way.
3) Bring out the Obama coalition to the polls.
She has #2 and #3 pretty well-planned and well-funded, and the Republican party already appears to be failing at their ground game. However, I feel like #1 would be decently harder. Not sure that even Sanders, Warren or Obama can convince a huge amount to come around to Clinton. Sanders has embedded very clear and influential ideas in their heads: the party is rigged and Clinton is corrupt. Regardless if either is true or not, he made those allegations a staple of his campaign and riled up a lot of people. Clinton has numerous issues beyond most candidates. I'm sure she'll get lots of them back, but I can't help but feel like she'll lose more support than most other candidates would. Corruption is a powerful negative attribute.
