Hi, Random Robot. If your goal is to be able to know where you are at any given moment on the fretboard, then
PlaneTalk will get you there ... that's really what it's best at.
Will it interfere with what you already know? No, I see no reason why it would.
How long will it take? How long is a piece of string?
There's nothing hard about it at all, in fact it's about as easy as it gets, especially as you're familiar with
CAGED.
There, that's my spiel.