I did this During the Telluride Blues N Brews and it was well worth it. If you ever find yourself in the area don't pass up the opportunity to run one of the most famous and scenic trails in the Rockies.
I wanted to post this because Black Bear has a reputation for being deadly, and most people translate that as difficult. It is not. Black Bear is a well maintained gravel road with a few rocky sections. One with very steep grades, tight switchbacks, and 1000ft dropoffs, but not a technical trail at all.
I had a few people tell me not to try it in a Ranger, but I hear that all the time. I'm so sick of hearing that Tacomas are these amazing off road machines and Rangers can't do anything. I would say that my truck was about the limit for size (even a new Tacoma would be too big), as some of the switchbacks required many-point turns to get around. Any 4x4 this size or smaller could run this trail. Really, a 2wd truck could make it but the trail is so steep you need the low range engine braking.
The steepest part of the trail, between the mine ruins and the power plant, is one-way down hill only. The slope exceeds 40 degrees in some spots and it is just wide enough for my truck, even a dirt bike could only pass in a few places. Black Bear along with Tomboy/Imogene Pass and the Million Dollar Highway make a great loop that can be done in one day. Either Telluride and Ouray can be used for the start point with the other as a perfect lunch break.