Scenic drives in Colorado are a dime a dozen, but one of my favorite roads is the stretch of Highway 50 that winds along the Arkansas River between Canon City and Salida. Plan for about an hour and 15 minutes of drive time if you slow down and enjoy the views. Watch for bighorn sheep climbing the canyon walls; if you're lucky, you may see them grazing by the side of the road. Admire the geology, and during the warmer months, wave to the river rafters as they navigate the rapids below you.
A few small towns along the way offer groceries, restaurants, camping, and souvenirs, but there's only one gas station (in Cotopaxi, which is roughly the halfway point). Several rest stops along the river allow you to stop, stretch your legs, and get close to the water.
Most of my bighorn sheep sightings happened in the early morning hours around dawn, but be vigilant when driving the canyon at that time because the deer are everywhere. Also be aware of black ice on the road in the winter.