In 2007, I drove from Page to Bryce over Cottonwood Canyon road through Cottowood Canyon, Grosvenor Arch to Cannonville and on to Bryce.
Not for the fainthearted, but you sound as if you have travelled a lot around that area.
At the time I was in a 1998 Toyota Camry with more than 100000 on the clock. I called in at Big Water ranger station, and they assured me I would be ok. Warned that there are a few spots of sand on the road, so you need to know how to handle a vehicle in loose sand. And you may come across folk on horseback mustering cattle and walking them back to Cannonville.
It is an unmade road. The 47 miles will take a couple of hours, and if you stop to photograph and explore the canyon and the arch, add another hour or two.
One of these great off the highway experiences which I treasure.
Lifey who loves the back roads