With her being "Bad Wolf" we could say the TARDIS sought her out when it was in trouble. Perhaps jumping to another dimension (hers). Or we could have him be a totally "new" Eleven who was Nine and Ten accordingly but n the dimension Rose is in, the Doctor never met her, which could work? If you'd like to play Rose, that's fine with me. I'm protective of her but as long as you don't play as she was when she left the Doctor (which I think was horrible on the writers part) I'll be happy. I loved Rose for season 1-2. Nine really helped her grow up and Ten helped her step out of the background a bit more, that's what I enjoyed about her. In the end, she ended up having her life wrecked and while her devotion to the Doctor was great to see, I feel like it ended up doing its damage when she worked for UNIT and all that, like Martha.

Oh yes, I know what serendipity means. ^^; I think a flaw with the TT is that you can only go back and to move forward, you must wait it out. I dunno. I forget, you probably could turn it the other way and move that way. Even so, I would love to deal with the TT at some point. My only concern and it's a bit out of left field but still..is that Hermione goes back in time to Remus' time and befriends him. Then later he's turned into his younger self. It all seems...weird you know? Like too convenient as if she may have had a hand in it. Which I know wouldn't be true (because THAT would be creepy) but you know what I mean? I'd hate to imply the potion was done out of selfish reasons, so an accident would be what was best. Unless it's post war, we could have Tonks and the child dead (though to be honest, I never bought the two together, much like most of the romance pairs in the books) and thus Remus needing a new lease on life, thus voluntarily changing into his youth?

Otherwise, an accident is a good way to go, it just depends on the timing in the time line.