I grew up in Ouray, wheeled the whole area for as long as I can remember. I vote you go for Black bear road. The sign used to (don't know if it still does) say "You don't have to be crazy to drive this road, but it helps." That's about a half to 3/4 day trip, Engineer pass from Ouray to Lake city over animas forks to Silverton, over Red mountain back to Ouray is a whole day trip. Last time I did it, it took 8 hours and the odometer read 98 miles. Be sure to take a camera, the scenery is second to none. Imogene pass to Telluride is cool too. All the Jeep rentals will have a map of all the roads. Stop at the Timberline Deli for a bag lunch. They open at eleven AM so order it the night before (they're open late) and pick up at 10 or so before you leave. (They'll be inside cleaning in the AM so you can pick up early). Just ask, they'll be sure to accomodate. The Bon Ton is a good Italian place for dinner, (a bit upscale price wise). And the Buen Tiempo is great mexican food. There's a great short hike up to Cascade falls just up the side street from the Deli. You can walk right up to the base of the falls. Again, bring the camera. About 35 miles up the road outside of Montrose is the Black Canyon of the Gunnison. deeper than the Grand canyon, but not as wide. No wheeling at the Black canyon, but a great view. Watch out for slow moving RVs on the trip to Montrose.
I wish I was going too, just no vacation time yet from the new job. Have a blast, and take a camera...