Is this the right way to think about progressing through the guides, and what suggestions would you make? I've listed her ages at each appropriate "grade" to help you out with where she'd be...
Thinking backward...
(what is the geography guide everyone keeps discussing?)
Rev to Rev - 7th grade (age 12)
RTR - 6th grade (age 11)
CTC - 5th grade (age 10)
Preparing - 4th grade (age 9)
Bigger - 3rd grade (age

Beyond - 2nd grade (age 7)
LHFHG - 1st grade (age 6)
and I think we're going to do LHTH as well as some other stuff for K, since it is our first year homeschooling. I have plenty of workbooks, but we're just going to have fun with it and move through LHTH. DD will be a young Ker, and always young for her grade. So, as recommended, I'd like to allow her to be at the upper edge of the guide, though I'm not sure how to do that. I've listed her ages above. Is there a way to extend things so that she will be at the upper end of the guide, rather than at the middle?
Compounding this is that I have a DS who is almost 3 years younger than her. Would it be advisable to think of combining guides? I see that we can do that later, although he'll be at the younger age of the guides and I don't want him to skip any of the guides...