I am going to purchase Lingua Latina (Pars I: Familia Romana) for homeschool instruction and have noticed that there are a number of companion texts. Is it necessary or beneficial to purchase any of these?
The Exercitia (Exercises) are definitely very helpful.
I have no experience with it, but “Latine Doceo” seems apt for your purpose.
http://www.pullins.com/txt/LinguaLatina.htm
I would suggest the College Companion for the series:
http://www.pullins.com/Books/01917CollegeCompanion.htm
It is excellent, and many homeschoolers have found it invaluable.