Just returned from a trip to Dead Horse Ranch SP. Rode from our site up to Sedona on my Harley {my kind of Toad}, and then on up Oak Creek Canyon. The first 15 +/- miles north from Sedona the road is in very poor condition with lots of potholes. There is absolutely zero shoulder with an occasional {but rare and short} pull outs.
At the north end of the canyon the curves drop to 20 to 15 mph recommended and the climb gets very steep. There are several miles of serious road construction {destruction???}, and you will wait 10 to 15 minutes for the pilot truck as he shuttles the north and southbound traffic up through the construction zone. This portion of 89A is posted, repeatedly prohibiting vehicles over 50'.
The road surface in the construction zone is dirt, mud, gravel and more mud as they bring in water trucks in a weak attempt to wash the serious dirt from the few paved road surfaces. This leaves the old asphalt with an inch of slimy mud which is not much of a problem for a car, truck, jeep etc., but no fun on a motorcycle... trust me. :S
Rather than reverse course and go back down we continued up to south Flagstaff and picked up I-17. Unfortunately the night before it had snowed big time in Flagstaff{yep that was May 9th}, the mountains were blanketed and the temperature on 17 was about 38 degrees at 1100. Once we got down below 5,000' it warmed up enough to be fun again and we spent some quality time exploring Sedona before returning to Dead Horse.
As noted repeatedly in this thread 89A is NO place for any RV over 30' and a far better venue for your trusty Toad {be it 2 wheels or 4}. If you are over 50' nose to tail you are not even legal on that stretch. Do yourself and everyone else in the area a favor and drive it in your toad, the ride is spectacular and not to be missed but a serious hazard for larger RV's.
I would add that the same holds true for the ride up to Jerome, worth your time but in a large RV... not so much. Don't miss the burgers at Haunted Hamburger...they are as good as the view and that is amazing!