Zion from Cortez can be a nice ride. Utah-95,Utah-24, Utah-12, Us-89 and then Utah-9 is a very scenic route. Zion will be warm but Bryce Canyon on Utah-12 is at 8,000 ft and is beautiful and a lot cooler. I was at Zion last month and the crowds are huge so bring some patience.

Have a great ride
Az Wingrider