I've put what I think the better solution for now to your particular situation might be, on your other thread, but if you decide to jump straight into home ed with a view to GCSE?s and A levels, then don?t worry hugely about course content at this point, the important thing is her laying the foundations of self-sufficient learning and learning not to depend on someone spoon feeding her. Where to look for information about things she doesn't know about, how to evaluate if those sources are credible, how to find more detailed information, how to cross reference something. Basic essay writing skills, and how to organise yourself when no one rings a bell and says start, stop, or do homework are the important skills, and she can do those using any subject matter.
(As Christmas is coming up, researching its origins and development naturally crosses quite a few subjects and could be a fun starting point while you sort out 2013)
We found CGP books very helpful, (and a lot more fun than Letts) as curriculem pointers, but once you get towards exams, (which you can do at any age you?re ready) you basically start by finding an exam centre that will take her, (this back to front way round is important for home edders) find out what exams and board/s they are licensed for, then go get the relevant books/resources for the syllabus.
Ie: our centre ?X? an independent school, does IGCE?s, and GCSE?s, and can offer most Edexcel, AQA CIE, and OCR exams, (but not WJEC) and we looked on the exam board?s websites at their course contents, if they needed classroom assessed coursework, and chose what fascinated.
We used the books as guides, and deepened and strengthened knowledge around what was in them according to what interested or didn't, (ie his knowledge of history of medicine is way deeper and far more than was needed for the exam, but his overall knowledge of American and Russian history is pretty close to the exam syllabus as he said there was just too much and the syllabus's he chose was what he considered the ?particularly interesting bits?.)
Whatever you decide to do, joining this group groups.yahoo.com/group/HE-Exams-GCSE-A_AS_Levels-OU-Others/ and lurking, will help you understand the many ways of exam aimed home ed for those wanting exams at the end.
HTH