My DS4 is currently in a Montessori program, but we're going to homeschool next year because the teacher doesn't seem to be letting him advance as quickly as he wants to. I've been very interested in it, though, and have attended an activity for parents where we got a lot of hands on use with the materials. I've also been thinking about whether we might do Montessori at home as well (We have a daughter who will be 18 months in the fall).

Anyway, someone recommended this to me, and I haven't gotten it yet, because I don't know what we're doing, but the point she made was that you could cobble together something based on websites, but that this had it all in one place, plus you'll know that you only have to buy the materials listed within these activities.
http://www.shop.montessoriprintshop.com/Math-Teaching-Manual-Primary-Ages-TMF-3.htm

Word on the web seems to be that Montessori Outlet (http://www.montessorioutlet.com/) is the cheapest place to buy authentic goods, but I also bookmarked this page with a list of DIY resources:
http://livingmontessorinow.com/2012/07/31/diy-montessori-materials/

As far as focus, I'd stick with whatever her interests are. I was concerned about my son's lack of reading skills (Yeah, he's 4, but I was reading very well at his age.), but a lot of moms assured me that it's just a developmental skill that kids seem to hit at different ages. For example, my son can sometimes say "cuh-aa-tuh" but not recognize that it's cat. That blending is the part that they say is developmental.

You might also want to look into the idea of a visual spatial learner. I know that it's controversial and full of anecdotal rather than "real" evidence, but after my son's high visual spatial scores (the highest the psychologist had seen), I started looking into it. It seems that these learners actually do better with whole word learning. My son's been playing Reading Eggs, and I've really noticed that he does seem to respond to words as a whole rather than separate sounds, though he *can* sound them out.

Most little ones aren't really reading at our kids' ages, but I know that seems hard to believe around these parts, since early reading is so often a sign of the gifted.