Suggest that from Dead Horse Ranch State Park in Cottonwood that you not take Alt 89 through Jerome. It's extremely narrow, steep, winding.
You could go a couple ways if you're heading to Hwy 60.
1) From Cottonwood take 260 back to Camp Verde and I-17 and pick up 169 into Prescott. From Prescott take the road through Iron Springs/Skull Valley (not sure of the name at present - check a map - although it might just be called Skull Valley Rd.). You'll end at Kirkland Junction on 89 and will then go through Congress to Hwy 71 to 60 and to I-10. (Hwy 89 from Prescott to Kirkland Junction is again, steep and winding.) We've driven the alternate route just mentioned numerous times and it's much better in an RV than 89.
OR 2) Cottonwood to 260 to I-17 at Camp Verde south to Hwy 74 (Lake Pleasant area) to Wickenburg and then pick up Hwy 60 to I-10.
Benchmark Atlases are excellent aren't they?