My motivation for methods actually stems from the repetition of concepts. Once you can fully understand a certain concept and do a few questions based around it, you are very unlikely to forget about it if you revisit it at suitable intervals. And although these concepts are always the same, the way you apply them greatly differs, which is where the variation of maths stems from. This is where things get interesting - each question has its own distinguishing features, and can be solved using a variety of different methods. You choose how you want to solve those difficult application questions, learn the different ways they can be approached, and you'll be on track soon enough.
Maths is, very obviously, a practice-oriented subject. Learning different ways to apply concepts to questions only comes with practice. Perhaps, if you feel like things are getting repetitive, set aside 10 questions from different topics each day that require knowledge of different things as a brain refresher, or whenever you are bored. Drawing from different aspects of the methods course may be less repetitive for you, and offer new opportunities to apply your knowledge.
Although doing questions from the textbook isn't exactly necessary, especially if you are receiving external booklets, it may be worthwhile to attempt the chapter reviews, which are more difficult in nature and segues nicely into VCAA-style questions. It is also helpful to go in order, since everything you learn is a build-up of what you already know. It's best to go with what VSV teaches, but self-learning is always an option if you are willing to learn it in a different order.