The problem I have found with mapquest is that it ignores the scenic roads and concentrates on the interstates.
Another way is to take I70 to Copper Mountain, take the road south to Leadville, the highest town in the USA at over 10,000 feet, then south to Buena Vista, Poncha Springs, then over Poncha Pass south to the San Luis Valley, and Monte Vista, or Del Norte and Hwy 160. Then over Wolf Creek Pass (remember the old CW McCall song of the same name?) through Pagosa Springs and Durango and the four corners, kids of all ages love to be in four states at the same time, then through the Navajo country, part of the painted desert and Monument Valley then to Tuba City and on to the Canyon. If the weather is good, it is a beautiful drive over the top of the highest peaks in Colorado. The view of the Sange de Cristo mountains over Poncha pass is something to enjoy, even though I see it several times a year on the drive to Denver.
Another way is Hwy 285 (takes off of C470 on the west side of Denver) to Fairplayand South Park, then on to Buena Vista and south. Check the hwy reports, if the wind is blowing in South Park and there is a ground blizzard, look for an alternate route.
You can also take I25 south to Walsenburg to hwy 160 and head west. Of course you have to put up with front range drivers and traffic through Colorado Springs and Pueblo, but once south of Pueblo, it is not to bad. Seeing I25 and the population concentration slong the front rance puts the plight of the people on the plains and over and in the mountains in perspective. At least this time of year you will be beating the KS, OK and TX rvers who drive slow and take up the whole road.
The route depends on how much you want to see and time. It will be about the same amount of time, no matter which way you take, even the mapquest route will take the same amount of time.
Questions? Let me know.