Myself and a group of friends just did Kokopelli this past May, and I've biked/driven much of it a couple times previously.
Trip Report
We only made it as far as Hideout in 3 days of riding...~90 miles ~4600 ft of elevation in 3 days. We did have a 3 day battle with mother nature though.
The beginning in Loma, Mary's Loop is great mountain biking, however the canyon between Mack Ridge, and the eastern-most edge of Rabbit Valley is pretty tough...you just about cannot bike it. We did a lot of hiking our bikes...its steep and loose. Next time I do the trail, I'd probably bypass that 2 miles. There is a ~1-2 mile stretch of singletrack between Cisco Landing and McGraw Bottom that you have to bypass by driving up to Cisco. After Dewey the elevation gains are pretty brutal on a mountain bike if you are not prepared for it. There is also a stretch of the trail near the trailhead for Top of the World that is questionable about whether it is drivable or not (I have different books/maps that describe it both as drivable and not)...I drove it once a year ago, and would never do it again...very narrow, and unforgiving consequences, and this past May it looked more eroded than a year before.
Bitter Creek is a great spot to camp. Hideout Campground down in Fisher Valley is a great campsite as well.
If you need any more info I'd be happy to chime in.