I have the priveledge of teaching Bible Greek to grade school students
(Latin, too). I use my own curriculum (or didache, whatever), and focus on
words that provide good derivatives (to bolster English vocabulary as well),
and simple tenses and case structure. Last year was my first year, and by
years end my 4-6th graders were translating paragraphs I gleaned (and
gleaned) from the Bible.
I think the best book for "a little Greek" would be "Greek to Me" by the guys
from Regent University, whose name I cannot remember, nor the publisher, but
their idea (memory pictures) was a marvelous help.
God bless all his faithful scribes!