I don't know about the campground. 89 is a pretty good road and the switchbacks are negotiable just taking your time and taking it easy.
There was a mention of traffic....and boy, is there traffic. 89 is nothing compared to the traffic in Sedona and just trying to get around...literally. Bumper to bumper, packed. It's ridiculous to me. Decades ago it was pretty serene, and pretty. Now, whatever you want to do, wherever you want to go, whatever you want to see....there will be a hundred others by your shoulder.
I've read of a lot of the reasons this has happened and some of them have property owners up in arms but that is neither here nor there; it is what it is. I went last about 6 years ago and said I would never go back; we haven't and won't; too many other nice places to see without all that aggravation (to me). Hopefully it will be much better when you go; we have gone primarily in the spring and summer. We now try to just stay up in Pinetop or Show Low, AZ - much better to us. If you stay there make a run (or 4 or 5) over to Greer if you like to fish. Catch some trout whenever you get hungry for them and have a nice time while doing it....