There is just no truly conceivable way that Hillary's approval would be in the 20s or even anywhere close to that.
Low 40s would be my guess. A bit better than Trump but not much. Most of it would be due to Congress blocking het at every turn, bringing up ridiculous charges, and running their mouths on cable about how horrible she is (in other words, how dare she be a woman outside the stereotypical role). There would also be a few minor moments of blunt honesty getting constant replay for weeks on the news.