We did some of your loop by car this November.
Try and catch, Zion, Arches and Bryce Canyon if it's not too chilly.
We did the Grand Canyon area in late April decades ago by car - it was chilly but certainly easily done with decent gear.
The canyon goes on forever so plot your route.
I'd cut over to Yosemite just for a day trip...the ride up to Glacier Point will be wild on a bike but worth the view. 9100' and no guard rails...
The PCH is brilliant north of LA but be prepared to be fogged out and cut inland...its just a drag in the fog.
There are a few photos here
https://picasaweb.google.com/113408714888195024530/PacificCoast
There are a few lovely roads that cut inland but you have to plot it a bit.
Drivers can get stupid and distracted along the PCH.
Try and catch Mount St. Helen's on the way north. - It's a quick couple of hours and worth it - nice ride up as well.
The area around Mount Rainer is nice but you'd have to suss out the good roads.
We'll be hitting Banff and then up to Alaska but that's after you get back.
BTW TomTom has a good offline GPS app with a Winding Roads feature that picks the twistiest route between two destinations. Kinda cool.
Also be careful with a phone sim if you are doing that.....coverage is spotty in the west for some of them.
Have fun.