Cumberland Pass between Pitkin and Tin Cup is the highest standard car road for summer use in the nation, and it is in good condition. 

It was constructed in 1882 to connect Tincup with the Denver-South Park railroad in Pitkin.  From the summit you can view over 50 miles of the Continental Divide, as well as many of the abandoned mines of the area.

The Cumberland Pass Road begins at the north end of Pitkin. It's suitable for either 4WD or 2WD vehicles.  There are a few fairly narrow places, still passable if each vehicles slows to a near stop and uses caution.  The place I like the least (although it has gorgeous vistas if you care to look) is the first couple miles as you head down from the top toward TinCup.