Hwy 24 is a popular route for RVers. As you get closer to I-70 you'll have some 6/7% grades to do but your motorhome is more than capable.
I wouldn't take Hwy 9 across Hoosier Pass (11,541' elevation). You'll have a very steep descent to the north for about 4 miles in length with hairpin turns. Instead, at Leadville on 24, take 91 to I-70 then east to Breckenridge and come in from that direction for an easier drive.
Full-timed for 16 Years . . . Back in S&B Again
Traveled 8 yr in a 2004 Newmar Dutch Star 40' Diesel
& 8 yr in a 33' Travel Supreme 5th wheel