Mike,
I've driven Cottonwood Canyon Road dozens of times. The condition varies dramatically denpending on when it was last graded. If it rains or if the Paria River cuts into it can be really bad or destroyed. I have not driven it this year. Obviously it has not rained much lately so the big concern would be how bad the washboarding is. And the washboards can be so bad you wouldn't want to drive it on a pleasure trip.
It is definitely true that if that road is wet it is impassable. I was once forced to turn around on that road when it was wet in my full size Bronco. The details of that turnaround are even amazing. The mud that forms is the stickiest most slippery I've ever experienced.
You should be able to get a current road condition report from the BLM visitor centers in Big Water or Cannonville.
The views are great from that road. We have used this road to hike Hackberry Canyon, The Box, visit a BLM dinosaur discovery, visit Grosvenor Arch and more.
Rob P.
