I think you can probably consider the mechanics of reading basically a done deal, and expect that she will progress rapidly in reading level if presented with interesting books that expand her exposure to higher-level written vocabulary and concepts in addition to engaging, appropriate, lower-level books that build reading ease and fluency. She might still need some brief instruction in the more obscure phonics rules and some of the more bizarre English spellings, but aside from that, she'll probably just take off. Inferring meaning of unfamiliar words from context is one of the primary ways that readers acquire new vocabulary, so I don't necessarily see the fact that she does this as a bad sign, as long as she is attempting to figure out at least some of the unfamiliar words.
