What about a combination of:
http://www.amazon.com/Scholastic-Dictionary-Spelling-Marvin-Terban/dp/0439764211/ref=pd_sim_b_4 (Scholastic Dictionary of Spelling, which sounds like what you are looking for)
and
http://www.amazon.com/Merriam-Webster-Childrens-Dictionary-DK-Publishing/dp/0756637589/ref=pd_cp_b_4 (Mirriam-Webster Children's Dictionary which has even more words and maps and is a great dictionary for roughly mid- to late-elementary kids)?

She thought she could, so she did.