Her actual options, growing slimmer by the day, will be to suborn the process, by finding some kind of leverage to persuade the superdelegates they should support the person with fewer popular votes and fewer delegates. The button she will push for doing this is to scare the supers with nightmare pictures of John McCain winning, by claiming he will be able to step on Obama's weak spots effectively in the campaign.
Her most honorable path would be to throw herself behind Obama and create all the anticipatory defense against the RNC "dirt-and-defamation" machine she could. More likely she will create D&D ammunition for that machine in an effort to undermine the party's winner in her own favor.
It is not an easy call on her part, invested as she is in being a persistent, determined winner of the DNC cominating process. But it would be the honorable call, however unlikely.