By all means, keep hammering on Bhengazi it's starting to seem like it might have some legs, however, I think the best avenue is sewing cog-dis and FUD over Hillary.
If it were me in charge of the counter-offensive, I'd astroturf up a HUGE feminist organization against her, or maybe an ecology of little ones over Hillary being complicit in the treatment of women in all of Bill's various scandals over the years, and I'd have timed it with the re-emergence of Monica.
Of course, the mainstream/rad-fem and original feminist.org's would all start screaming that it was just an astroturf .org, and then the astroturf .org's should start screaming back about why do all the legacy feminist .orgs support mistreatment of women?
It would be epic, and a two-fer, doing damage to the legacy feminist .orgs at the same time.
Overall though, I have a hunch that the whole "FRIST FEMALE POTUS!" bandwagon won't be nearly as big as some think it will be. I think that the female voter demographic's ability to suddenly dislike a female candidate "because, uh... reasons", above and beyond policy and party is vastly underestimated.