Hi, Tracy. My hesitation would be that the Track A lesson plans also add the First Steps reader and Delightful Handwriting copybook. I wouldn’t recommend those until the child is reading on the level of Delightful Reading, Level 3. So while you could use those Individual Studies lesson plans for your 6yo, by the time you take out the reader and copybook, there’s not much left that you couldn’t just do on your own without the plans: math each day and science twice a week, then do DR Level 2 for 10 minutes or so several days a week. You probably don’t need to purchase daily plans for that.
It might not take all year for your child to get through Level 2, so you could easily start Level 3 and the Individual Studies plans at that point if you wanted to.