In her primary campaign, backed by the entire party establishment, infinite cash, and with unmatched name recognition, and with no real attacks from rival Democrats, she is repeatedly kicking herself in the foot and losing ground to someone who describes himself using the Republicans favourite attack word. And this is approximately what has happened twice.
She's a terrible campaigner and is in real danger of losing to almost anyone from the R side. Biden and even Sanders are probably safer bets.
One interesting thing about Sanders- he'll obviously get his base vote but he isn't targeting moderate Democrats, he is trying to appeal to social conservative Republicans. He gave a speech at Liberty University, and while he talks about abortion/racism, his main talking point is special interests/inequality. With the pope due to arrive with a similar message, if he's canny enough things could get interesting. He does get very high votes from Vermont Republicans, who are mostly rural and probably socially conservative.