My ebiker wife and I are going east to west, and recently rode from Pueblo to Canon City. We took advantage of the circa 10 mile Arkansas River MUP trail (mostly paved except for short stretches) from Pueblo that winds up at the Pueblo Reservoir Visitor Center which sells drinks and snacks and has restrooms and water. Later that day, we used the 4 mile or so Arkansas River MUP trail (smooth limestone gravel) to get into Canon City. Both are highly recommended, unless flooded (always a risk if the word "River" is in the name). Made us wish the trail was completed between the two cities entirely along that river. Bike trails at the end of the day are wonderful, imo, as they give you peace and quiet, coloring my opinion of the entire day.
We did not enjoy Rt 9 WB from Hartsel to Fairplay, but I have no suggestions on reroute. The traffic was very heavy (maybe 5x Guffey to Hartsel), pickup trucks enjoyed scaring the crap out of us at 75 mph, and we had a lovely time fighting cross/headwinds going uphill. I shudder to think of what that would have been like if it had been raining that day, but your tolerance may vary (eg., my wife would definitely never ride that road again).
Rt 9 WB over Hoosier pass was busy as well but folks were better tempered, or so it seemed. Currently taking a week off to see grandchildren before continuing up to Missoula, on our way to Astoria.