In Utah; Near Moab, SR 128 from I-70 to Moab is worth seeing.
Also in Moab area, Archs National Park is a nice destination.
You could follow US 191 about 40 miles south of Moab to SR 211 which deadends at Canyonlands National Park...well worth your time. Be certain to stop at "Newspaper rock" for a view, but then follow the road to its end you won't regret it.
Southern Utah - After Moki Dugway you could go over to Halls Crossing and take the ferry across Lake Powell.... then follow 276 north to 95 to 24. SR 24 to Torrey is a spectacular road. Of course, Torrey is where you'll hook up with SR 12 to Escalante.
In the northeast part of the state Logan Canyon from Bear Lake to Logan (US 89) is one of our more beautiful roads. Stop at one of the look outs to get a picture of Bear Lake, the stunning turquoise blue color is due to limestone suspended in the water. It is gorgeous!
Colorado; You already mention the million dollar highway, nice choice! In that area is also SR 145/141, Delores canyon road from Cortez to Grand Junction.
A bit north of Grand Junction on I-70 is Glenwood Springs. From Glenwood Springs, take SR 82 through Aspen, watch out for all the exotic cars and Ducatis on the road... about 22 miles after Aspen you will go over Independence pass
..it's a jaw dropper!!
If you follow it to US 24 you can work your way down to the 550 (million dollar hwy).
35 miles west of Denver is the Mt Evans road. Mt Evans is the highest paved road in the lower 48, and an unbelievable road to get to the top.