Lest We Forget is a series of Adventist History unit studies designed for upper elementary and junior high students.  The 5 part series features readings, study/research questions and more.   They are all free .pdf files .  Be sure to check each link for the separate files.

Lest We Forget – Beginnings of church history

Lest We Forget II – Organization of the church in the 1850-60s.

Lest We Forget III – General Conference of 1888

Lest We Forget IV – The Southern Work , includes links to mp3 files

Lest We Forget : The Total Historical Picture –  excellent timeline resource