If you are coming through Durango go through Pagosa Springs over Wolf Creek Pass.
Next, heads toward Lake City, through Slumgulian Pass.
You can thank me later.

 

550 is great and i would continue up towards Delta and get 65 from Cedaredge to Mesa...330 to I 70...go east a couple of exits and grab 82 which will take you thru Independance Pass and Aspen...pick up 24/91 to I70 again...go east a few exits till you hit 40 to Granby...take 34 thru the Rocky Mountain National Forest and into Estes Park. You can head south from there and go towards Canon City(50) and just west of there is the Gorge...continue west to Montrose...550 south to Ridgeway..62 to Placerville and take 145 south to Cortez....and if you haven't done Utah...head up towards Moab...!70 west to 24 south and 12 thru Escalante and Bryce Canyon...one of the favorite rides ever....check out the Burr Trail in Boulder Utah....you will have to turn around because of gravel but you will be freaked out by the sites on this road.....

I would ride Colorado and Utah every year if i had a chance.....

 

If your coming from the west into Colorado, I would plan my route thru Zion N.P. and definitely ride hwy 12 into Torrey. Colorado is heavily loaded with great roads for motocycles. Draw a line thru Denver north to south, anywhere west of the line is GREAT riding. The route Jeffbarb posted would be nice, only I would take 550 ( million dollar hwy) from Montrose all the way to Durango then west to Cortez. It is an Awsome road. Others have listed great places to visit as well. Just a matter of your amount of time to explore.
Good luck on your Trip!

 

How long are you planing to stay in Colorado? I live just SW of Denver and know a few roads...mostly the eastern slope..here's a couple must do's..my opinion..
Pikes Peak(just west of Colorado Springs)...interesting and challenging..a 20 mile trip from bottom to top,7 miles of that are unpaved..a sandy,gravel..hard pack with washboards and plenty of switchbacks and a pretty good grade.very doable,I was there just a few weeks ago..14,140 ft elevation..
MT Evans(west of Denver between Evergreen and Idaho Springs) this is the highest paved road in north america at 14,171 feet..you can take 103 from either way (Squaw pass) up to the entrance,which is a great road all by it's self,then the park road is 14 miles to the top..all paved,very steep dropoffs,and no guardrails..very un-nerving the first time, again lots of switchbacks and steep grades..this whole trip,Squaw pass and MT Evans is one of my favorites..I only live about 30 miles away..
If you start at Colorado Springs and work your way north,take 67 north through Deckers,pick up 126 into Pine Jct (another great road) go right on 285 to 73 north to Evergreen,then follow 74 to 103 (left) to the Mt Evans trip,after Mt Evans you end up in Idaho Springs..take I70 west about 6 miles to rt 6 to the north,catch 119(left in about 3 miles) take 119 to 7 (the Peak to Peak highway) all the way to Estes Park,go west on 34 which will take you to Rocky Mountain National Park and Trail Ridge Road (the highest continuous paved noad in north america) (Mt Evans is not continuous,it goes in and back).which will take you on 40 mand back to I70..all in all about 3-4 days worth..
Pm me if you want some more info.

 

You guys are great! Thank you so much for all of your recommendations. I'll be working on this after work today (booking hotels, tracking miles). We plan on exploring CO for 10 days or so and heading back to CA via UT. We went through Moab a few years ago; our plan is to experience it again and to add Zion to our UT experience. I'll definitley take a look at riding hwy 12 into Torry (Mikey 1450's suggestion).
I'm really getting excited about experiencing CO. Our original plan was to book two vacation routes for next summer. The other tour would be to Banff and Jasper Canada. Our plan was to go on the trip with the best weather. (what can I say, I hate riding in rain! Fogged up goggles suck.) But after all of your great suggestions, my vote is to just book CO and pray for decent weather.

 

Torry has a nice Days Inn and at the end of town is a place called Cafe Diablo....not cheap but great food........

 

If you are in Durango, head over to Pagosa Springs and stay on 160 up to south Fork and then 149 up to 50 then back along the lake to 92. Pick up 133 at Hotchkiss then 82 down through Independance Pass.

Mt Evans is all paved and is the highest paved road in North America.

Rocky Mountain Park is very pretty but a bit busy.

In the west, Hwy 141 is a beautiful canyon ride. If you end up in the southwest, spend some time a Mesa Verde - nice ride in and out and very interesting.

If you stay off the freeways, it is tough finding bad roads in Colorado. I also second others comments about Utah, if you can spend some time there, do it.

 

without all the tourists and weekenders...
* ride through Sedalia, take a left on 105 to Palmer Lake then east through Monument, (heading over I-25), and pick up Hwy 85. Head North towards Denver. Stop at the Canyon. The road is yours. A great biker bar, but forget the name, as you get close to Denver.
* Cottonwood Pass from Buena Vista to Almont is spectacular but is a hard dirt packed road. I did it on my Street Glide, slowly, but the window of opportunity for touring bikes is small on this road, maybe from mid-July through August. Once you get to Almont, turn R to Crested Butte. which in my opinion is the last true mountain town in CO. It lies in Paradise valley, and you will understand why they call it Paradise when you ride through it. Be sure to stop at Camp 4 Coffee shop. Best cup 'o joe I have ever had. I rode 8 hours round trip from Denver to this shop just to get a couple of pounds.
* Black Canyon of the Gunnison. I think it was recently given National Park status so may be busier these days but head south out of Crested Butte and west out of Gunnison to the Black Canyon. It's filled with 50-70 mph twists and turns. Reminds me of South Dakota. You hear lots of talk about beautiful "mountain riding" and it truly is beautiful but for me, doing 15 to 30 mph through switch backs just aint my bag. Banked 70mph sweepers is my thing and if yu feel the same, this ride will trip your trigger.
* Fort Collins through the canyon to Estes - Lyons and Boulder: , (stop at Red Hill Motorcycle Werks in Lyons. Incredible custom motorcycles on display and way kool folks running the place). Sweet ride and you end up in Boulder for your "green" fix. The "Kitchen" restaurant on Pearl street rocks. Try the hanger steak.
*Hwy 24, west of I-25 through Woodland Park. Straight shot for a good 50 miles through beauty. Crank it up to 85 mph, hit cruise, and kick back.
* Salida, ( not to be confused with Sedalia): Riding through the canyon along 50 is sweet.. Stop off at the Royal Gorge but be careful not to stop for hitch hikers in Canon City, they have more Federal and State prisons than any other area in the country!
* Four Corners: anywhere and every where. Has a character all to its own. Ride through the Painted Desert, straight road, (no really, it is straight / true), for 100 miles and not a soul in site on a week day. I nominate this road, (tied with another in Wyoming), as the best place to feel alone.
* If you make it to Denver, you have to cruize the most infamous City street in all of Denver: Colfax, (or as I like to call it, the Cold-hard-fax). it's in the heart of the City, running past the Capital. Its appearance is unspectacular, but the people, bars, and eateries rock the house.
Hope this is helpful. Enjoy your time in Colorado.

 

And once again - thanks for all of the recommendations.

 

The ride Agent Orange describes from Colorado Springs is a terrific ride. I might suggest adding two roads though. While riding 119 towards 7 you will encounter road 46. Take it. It's a right turn and will take you to hwy 93. Then turn North(L) and follow to road 72. Take it. Turn left. It will take you back to 119. At 119 turn right (a challenging turn in itself) and continue on your way to 7. Believe me, you will be glad you did. There's always a chance of rain in the "high country" but usually in the afternoon. If you are a HOG member and recieve the touring handbook any of the roads highlighted as scenic will not dissappoint. Thankfully you've recieved great suggestions from forum members and the difficult part now is deciding which ones to take. I'm from So Cal originally and have ridden alot there. Believe me when I say, your trip to Colorado will be the one all the rest get compared to in the future. My bet is you will be back after your first one. Best of luck, have fun and bring a helmet cam if you have one or can get one. For more info go to www.motorcyclecolorado.com