Route through Westcliffe to Walsenburg is all a two lane road. Nothing tough, but CO 69 isn't a speedway. Some places 50 MPH, some up to 65 MPH. Westcliffe to Walsenburg is sparsely populated. Fill in Salida or BV.
Salida to Pueblo via Canon City is a US highway and thus a little better quality road. Even so, along the river out of Salida it does follow the river with some areas of 35 MPH, others of 50 or 55 MPH so it isn't a faster trip all the way through Canon City. You do have the hassle of driving through Canon City, but after that is smooth going all the way to I-25.
Don't do Denver.