The Kokopelli is a great option. This trail was established by COPMOBA in the mid eighties and is a real classic. Two other trails worth considering are the Paradox and the Tabeguache. Both of these trail were established by COPMOBA as a follow on to the Kokopelli. All three are located such that they can be ridden together as a single trail called the Grand Loop. The total distance is around 380 miles combined, with over 48,000 feet of climbing and might just be the premier bikepacking challenge in the US. Detailed maps of each trail are available at
COPMOBA.org, but you do have to be a member to get them. Even with the maps route finding is a challenge on the Tabeguache and especially the Paradox.
It is my plan to ride the loop in the spring or fall of 2011 over the course of 10 days or so. I will start a separate thread as the plan becomes more organized. It would be great to do this with a group of up to six riders. It can be done unsupported but having a single sag vehicle for food and water would reduce the difficulty level as water sources are few and have to be planned for. Most of the trail can be driven, but not all, so a few bypasses would be necessary for a vehicle.
In any case it would be great to preview one of the segments this fall as a warm up to the complete loop.
Here is a satellite image of the loop.
A larger version is available here.
http://bikepacking.net/images/3Droutes/GLR.jpg
Another option to consider is the Cathedral Valley loop near Capital Reef NP. Is is a shorter distance of 60 miles and can be done over the course of two leisurely days. Optional loops are easily added to increase the distance. This would be a great ride to test out the new bike and associated kit. I did this ride about 4 years ago during heavy rain. Riding through flooding washes was interesting to say the least.