I have become a little bit of a Latin curricula junkie (it's the honey bee in me). I have Henle Book 1, Visual Latin, Prima Latina and Latina Christiana I and II, I Speak Latin and Lingua Latina. This does not include the assortment of google books I have found and printed. There are multiple Latin curricula in the public domain, as you would expect, the only problem is that they don't normally have answer keys. I found this one before I was introduced to interlinear texts, so here is my favorite approach that is more in line with a grammar based approach to teaching.
Elementary Latin by Minnie Louise Smith (1920)-
The introduction claims the goal of this program is:
"to make Latin seem alive; to give the first year study a value for general culture; to minimize the difficulties of beginning Latin; to prepare thoroughly for the second year of work"
The lessons are focused, incremental and well laid out. There are multiple exercises per section with excellent variety. Honestly, even if you don't use this particular text I recommend you look at the exercises to add options to your own curriculum. These activities include vocabulary, translation (to Latin and from Latin), grammar rules, derivatives, word drills, form drills, translation of short texts, answering questions posed in Latin to be answered aloud in Latin, and questions covering the grammar. By the fifth lesson you are beginning to read Latin and there are over 40 connected passages for your student to read through. By the end of the year you are even writing in Latin. I haven't mentioned the brief cultural bits of information spread throughout the book (with over 100 illustrations of Roman artifacts, ruins, etc. with explanations of their importance).
In the first few lessons it covers 1st declension nouns, 1st conjugation verbs present tense, direct objects (in English grammar) and then introduces the genitive case and the conjugation of Sum. Second conjugation, adjectives and the four principal parts come next. So, it is a smattering of parts of speech but you use them in a variety of contexts and it gives you enough background to make sentences. One of my struggles with Henle is that we spent so much time going through all the nouns that I didn't ever feel like I could complete a thought. (I guess if you use Prima and Christiana first that isn't the case). There are some that are truly opposed to this method - but I think that her approach can work.
She assumes that you are doing recitations and form work consistently to support your learning. I have realized that older books just assume recitations and we don't even know what that means. (Another guide for memorizing is the Dowling Method - I realize that his recommendations do run counter to her approach. His clear outline of the structure of Latin gives you the foundation needed to be more successful in a more piecemeal - but honestly more fulfilling- program. It is the rare person who has the discipline to do what he outlines!)
The appendix is an amazing resource. It includes some great passages for reading and translating (Story of Ulysses and Caesar), songs in Latin (with music notation), a list of common Latin phrases (including all of the state mottoes in Latin) and well known Latin quotations (Cicero, Caesar, etc.) The best part is that she clearly outlines the goals for first and second semester - what mastery looks like! She lists all the vocabulary covered, inflections you should memorize, principles of syntax, word formation (prefix/suffix, etc.), a derivation notebook (with the 20 most important derivatives each semester), oral sentence work and Latin readings. She also outlines how you can begin writing Latin sentences by the end of the second year. I feel like she is not just setting pie in the sky goals- she really can teach you Latin.
But that is not all! She then includes a reference chart covering all the Latin grammar you'll need to know. After that, she provides definitions for all the English grammar you'll ever need to know. With a little bit of work you could use it for English grammar recitation (like the MP program). The book ends with a Latin-English/ English-Latin dictionary.
This is truly a great resource. It is meant for high school students but I think it could be used slowly and successfully with younger students. For the mom who wants to learn Latin I think it has a lot to offer. Again, I emphasize that you must do the recitation and extra practice so that you memorize the inflections and syntax. YOU JUST HAVE TO MEMORIZE (that is the one thing I have learned from all my curricula). That's one reason I like the appendix - she outlines EXACTLY what you need to know. I promise my other reviews won't be as long - this one just offers SO much.