It's been a while - the last serious work on this project was completed six weeks ago at the time of writing. However, since then we have developed a proper action plan.
Last time around I removed all the screws and fasteners from the deck underlayment; I knew I would use this material for something. It turns out it will be great for manufacturing the furring strips we need for underlayment below the new deck.
I began the milling of the furring strips by cutting the timber into seven foot lengths, and discarding anything shorter than five feet. It was a beautiful late October day, so I did the basic cutting outside with the circular saw.