All roads in Colorado are winding!
From I-70 you're probably looking at either Hwy 9 or Hwy 131. No issues on either.
If taking 131 to Steamboat you'll avoid Rabbit Ears/Muddy Passes.
If taking Hwy 9 you'll cross Rabbit Ears Pass/Muddy Pass on Hwy 40. From the 'Mountain Directory of Truckers & RVers':
Westbound descent you'll have a 7% grade for 7 miles with 45 mph curves. Then you'll have an escape ramp to the right. Afterward you have 3 more miles of 7% grade.
Get into lower gear before starting downhill; not in the midst. This saves your breaks. It's a popular RVer's route so it's doable. Just take it slow as others will be doing.
Hwy 40 is a major two and sometimes, three-lane, good highway... enjoy!