I can't believe I actually finished this. The Codex has occupied way too much of my free time over the past couple of months, and it's thanks only to hints from Dirty_Bird and BigNastyBrain that my brain didn't melt out of my ears.
I really enjoyed the story as a standalone. But the puzzles are in a class by themselves. I'd never seen anything like it before, and now I fear other, lesser puzzle caches will be spoiled for me.
Thanks to Dirty_Bird and BigNastyBrain for a great experience! Someday I hope to get to New Jersey to see what the on-the-ground challenges look like.
Cheers from Denver,
Jon