I agree that Willis' book is good and also rather hard.
The hardest part is seeing the "grid" change with key changes. I have other traditional scalular methods I use to play as well and it's still hard seeing outside of the little world where your hand is the board.
Willis' method assumes that you know
A- The chord tones in any basic non-extended chord
B- Where those notes are on the fingerboard.
After that - he's really just showing you how to use the symetry of the neck to economise your motion.
Take the idea that you are never more than a whole step away from a chord tone. This is true. But you can only benefit from that info if you know what the chord tones are - and where they are on the board. Willis method has a round about way of getting you there - by turning each chord into a geometric shape. But he starts you off in the first 5 frets and uses lots of open strings - so the "shapes" aren't immediately appearent.
Overall - I think even Gary might agree the book could have been done much better.
Great, helpful ideas - spotty excecution.
BTW - Willis claims he sucked at math in school but was a wiz at geometry and that's how he turned the fretboard into his bitch.
I sucked at both - so there ya go.
