I have enjoyed sweating my way through "Part One" of Paul Hindemith's bootcamp-esque Elementary Training For Musicians. I was initially dismayed by Hindemith's cosmically grumpy introduction which is rife with abrasive/exclusionary language, but I'm glad I shrugged off his negativity and stuck with the program. If you relish tasks that are designed to sharpen your musicianship into a fine point and require 110% of your mental bandwidth, Hindemith's book is for you.
Blog update: posts will be fewer and further between as I begin to focus my creative energies on a new orchestration project that will keep me busy Sept-Oct. I will be excited to share more when I'm further along!