First Language Lessons for the Well-Trained Mindand we started a new grammar curriculum with him called Easy Grammar. So far, we like it. Other than a few differences in terminology, the transition has been smooth. It's fairly rigorous without being overwhelming. Unlike First Language Lessons, Easy Grammar isn't scripted for the teacher. That makes it easier for T to do on his own so we can spend our together time on subjects that need more input from me.
We've only been using Easy Grammar for a couple weeks now, so I can't say too much about it from experience. If my impressions change as we continue to use the curriculum, I'll come back and update this post. For a comparison of Easy Grammar and First Language Lessons from someone who has used them both more than I have, see "Easy Grammar Vs. First Language Lessons" at the wonderfully named blog, "Weird Unsocialized Homeschoolers.