Hey famontherd, welcome to the forum. Try Cortez, Mesa Verde Nat'l Park, and Durango, CO. All fun places to go and see. Make sure you take a train ride from Durango to Silverton, CO while you are at it.
Ya have to drive the Scenic Byway that goes from Cortez up to Teluride and back. I have been camping for over 30 years and that drive with many waterfalls and beautiful scenary was the best i've ever seen. The train ride like the other poster said is a must. All of Colorado is beautiful though. We stayed in Delores north of town at an out of the way rustic camp ground owned by a farmer/rancher right on the Delores river. There was a pier into the river and we caught enough trout to eat every night. The best part is we were the only ones there covered by euks.
We stayed a week twenty feet from the river. Paradise
By all means...do NOT miss Rocky Mountain National Park!!! If you have a Golden Pass you can stay for 1/2 price and no entrance fee! You will see GREAT wildlife!!! Big Horn Sheep, Moose, Elk, Mule Deer....all right in the road!!! Fantastic vistas and views....beautiful scenery!!!! DON'Y MISS IT!!!
Also, if you drive up I-25 to the Wyoming Border, you will see a few Camels and the Bison Herd!!!
One of the best drives in Colorado is the Trail Ridge Road in Rocky Mt. Nat. Park. Trail Ridge Road is the highest paved road in any North American Nat. Park. Stunning scenery at the top and all along the way. As you follow the road up from E. to West and as you leave the park from the west you will pass by Granby and Grand Lake which also has spectacular scenery. From there I would drive to I-70 and take highway 6 which is the exit before the Eisenhower Tunnel. This road follows absolutely spectacular scenery and will absolutely amaze you. This road will wrap around to Dillon and reconnect to I-70. Keep heading westand head to Vail and exit 171 which is directly west from Vail. This highway (24) heads south to Leadville and is one of the most beautiful drives in Colorado. From Leadville you can travel south and then West to Aspen. You have to be careful though while driving over Independence Pass which is roughly 20 miles or so from Aspen because there is a length limit of 35 feet if I am correct. The reason for this is that on this road 7 or 8 miles or so from Aspen the road is cut right out of the mountainside and you barely have one lane. Straight dropoff if you go down. The Fall colors are beautiful. As you head into Aspen it will just stun you. The homes all over are amazing and the mountain is beautiful. As you drive through Aspen look to the east and to Red Mountain (with all of the huge homes on it). Each one of those home are worth at least 5 and to 50 Million. Do not get gas in Aspen unless you want to pay roughly $4.00 per gallon. 30 miles up the North on 82 is Glenwood Springs and gasoline there is much more reasonable. Once you get to Glenwood Springs the hot springs there are amazing. Great side trip if you have kids or if you are tired. Any questions feel free to email me. firstname.lastname@example.org
If you happen to be around Cortez or Deloris. trek on up around Norwood and then visit Miramonte (SP????) resevoir. Most incredible trout fishing. I usually go around mid October. I was catching rainbows up to 3 or 4 lbs each. There are camping places to but you have to dry camp. Nice mountain views too. If you happen to have 4 wheelers or a jeep there are lots of mountain trails. However mid October is hunting season so be careful.