Hermione had wasted no time, once she finally admitted to herself that she was unhappy in Magical Britain. The only person she really cared to talk to, anymore, was Harry, and even then, they did not get together often – It seemed that whenever they were together, the conversation inevitably turned to Ron, or the War, or some other unpleasant subject (she didn't know how Harry and Ginny could stand it [actually, that was a lie: she knew that Harry really didn't handle it well, but Ginny loved the fact that Harry needed her to be his emotional crutch. They were painfully co-dependent.]). She still saw the Weasleys occasionally, of course. She and Andromeda and Teddy were always invited to Weasley family holidays, since Teddy was Harry's godson, and Andromeda was his guardian, and none of them had anywhere better to be, but even Ginny and the twins had learned to give her space, over the past four years, and they had not grown close again. Their history was too deep to for distance, and too painful for closeness.
So when she finally admitted to herself that she was unhappy, she considered the job offers she had turned down at the end of the war. Almost every department at the Ministry had offered her a position. The exception, of course, was the only department she would have actually considered: Mysteries. They had blacklisted her after the events of the 1993-1994 school year – though they were more concerned for her refusal to comply with their secrecy protocols than her overuse of the Time Turner itself. She reconsidered returning to Hogwarts as a teacher, or doing something else in publishing, and even Fred and George's open offer to come and develop new products with them. None of the offers was any more appealing than it had been in 1998, even if the positions were still available. Her post-war celebrity finally seemed to be dying down after all.
After two weeks, she realized that she needed to get away from Magical Britain entirely. The extra work she had done (on a completely unofficial and freelance basis) to ensure that rogue Death Eaters were rounded up (or just disappeared) throughout Europe was completed (though she would wait, as planned, to retrieve her parents in 2007. One really couldn't be too careful, after all). Her editorial position with Pressgap was a dead-end, unless she wanted to wait around another hundred years for the owners to die and take it over. She hardly knew anyone personally, and couldn't really meet anyone, given the way people still talked about her, even if she was no longer constantly in the papers. There was really nothing left for her in Magical Britain, except Harry, and he would owl her anywhere, so he hardly counted.
So, then, she decided, she would just have to go back to the muggle world. Perhaps she would get a proper university degree. There were, at the very least, more career options in the muggle world, and she could be relatively certain that most people wouldn't already know her name when she introduced herself.
That was the hardest part, really. From there, it was difficult, but not impossible – muggleborns hardly ever attempted to return to the muggle world once they had been gone for a while. Generally, if they went back, it was just when they graduated from Hogwarts, and the school arranged to falsify qualification exam scores so that they could just get a job. Hermione, in contrast, would not settle. She wanted the proper background information so that she could enter any decent university and pursue… some program of study. She was, of course, a bit old to be entering Uni, but then, she expected there would always be some students looking to change careers.
She spent six months studying feverishly for her A-Levels, putting in arguably more work than she had for her OWLs and NEWTs combined, as she had been ridiculously advanced over her peers back then, rather than playing catch-up on entire subjects. She travelled to London to sit the exams independently and research what other documentation would be required for her entry into a university program. After several judicious uses of memory charms and a few simple forgeries (she couldn't very well turn in a letter of recommendation from the Headmistress of Hogwarts, School of Witchcraft and Wizardry, though she was sure Professor McGonagall would be happy to write one), she was properly enrolled at King's College. She wrote several letters, and then made a few calls to her uncle, and then one of her cousins on her mother's side of the family to sort out a living space. She resigned her editorial position, and corrected the last proofs she would ever have to deal with. On the fourth anniversary of the Battle of Hogwarts, she made the announcement to Harry and the assembled Weasleys: she would be moving to the muggle world on the first of July, to return to school in the fall.
There was, as expected, an uproar. The only person who seemed to support her choice to go back was Harry. Hermione shrugged internally as she fended off red-headed objectors. It was, as she had carefully calculated, far too late to change her plans now. She was gratified by Harry's congratulations and the twins' stunned incomprehension (as they strongly believed that speechless awe was the highest form of flattery), and left the celebration early to continue packing.