It was good to see your picture of the smashed truck in your report on the Skutumpah Road. That was one of the first places I ever went on my KLX650C when I first got it. I almost hit a deer on the way back. I was so shaken that I had to load my bike in the back of my friends truck for the ride home.
Have you seen this book?
I bought mine in the Safeway in Page, AZ many years ago (before there was a Grand Staircase - Escalante National Monument). Here is a link to the publisher: http://kelseyguidebooks.com/?page_id=51
It has some great history on the area. There is another one about hiking around Lake Powell too.
That canyoneering looks like a good time!