I had to look into the RCM question a whole while back because of my first experience. As someone said, it is not a method book so "it" doesn't instruction - the teacher needs to. I was doing RCM when I started violin as a new instrument as an adult. There is a technique book and repertoire book, and the two go hand in hand. Say you're playing C, G, F and D major scales and their relative minors in "technique", your repertoire would also be in those keys: "technique X" in technique will show up in repertoire. How to do these things should be shaped by the teacher. ..... If you're going for exams, then theory comes in at around grade 4 or 5, and that would be a third layer.
What I did at the end after everything had gone awry was to buy the syllabus book itself which showed which skills and such were aimed for at each grade level. I also found out that the syllabus book suggested a whole bunch of pieces for any grade level, and the RCM repertoire book only had some of them. For repertoire I think they tried to have several for Classical era, several for Romantic era etc. I think this would be the same across all instruments.
Years after I stopped all this, and there was a lot more information on the Internet, I saw real teaching of some of the things I had done RCM-wise. You don't just play an etude, and if it sounds ok, then you've "done" it. There is a point to that etude, a thing you should be learning and aiming toward, and ways of getting there. A lot of this had been missed. In that sense, the fact of a teacher being there isn't enough: the teacher also needs to be doing the teaching because there are no pointers like there might be in a method book.
