Line of study with RTK

Hi all, I’ve decided to pick up Japanese again (on and off for about 13 years now, never got very far because I’ve never been good at keeping track of all the things needed for Japanese).  
I had never heard of RTK before and think the decide and conquer route might work better for me but I don’t want to waste time.  What is the best way to go about it?  Do you do the whole book, go to two to learn readings, then do Vocab and grammar after months and months of Kanji?  It might be worth it if it works, but it also seems like a lot of time to put in before getting any kind of communication studies in.  Any help would be greatly appreciated.

RTK isn't about learning the readings, it's strictly about learning to write kanji from English keywords, I would personally avoid RTK2. After doing RTK1 (and 3 if you want), at that point, you best best isn't to learn readings, but rather to learn vocabulary. You'll naturally pick up the reading for the kanji as you learn the vocab. If you have time, you can do grammar on the side, or you could use a course that focuses on spoken language, JSL or the like, while work your way through RTK. If you don't have the time, then yea, spend 3-4 months on kanji, and then when you learn a new word through whatever course you choose, be it Genki, Yokoso, or JFBP, make sure to learn the kanji with the vocab.
I personally would go through RTK1 to learn to write the characters from the keyword, and then work on the readings, but if you're not interested in learning how to write the characters, then there might be more efficient ways to learn to read them. For the readings, I used RTK2 (and then RTK3), but there might be more efficient ways available now. The comments above about working on vocabulary to learn readings might be a better approach. I think that the sound primitives (a part of RTK2) are worth the time, though, in any case.
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Regarding RTK2, I "mined" it for the information I needed.  That is, I created spreadsheets with all the "signal primitives" and learned as many as I could.  What I did not do was try to memorize all the "exemplary compounds".

As I like saying, you'll know when it's time to use the information in RTK2.  If you don't know what to do with RTK2 then it's too soon for you to be using it.