Mountain Biking (self guided)

You can easily organise a cycling trip yourself. Try renting a bicycle with one of the tour companies that also offer tours. Take a bus from Terminal Provincial Minasa Yungas (or a private van from where you prefer) to La Cumbra at 4,650 m and go from there, or go directly to the beginning of the North Yungas Road, from where it is only 30 km, which may be preferred if the weather at La Cumbra is bad—with mist you will not be able to take pictures anyhow. Buses usually have enough space in their luggage compartment or on the roof. You can stay in the region or head back directly to La Paz with the next bus from Yolosita.
The "Death Road" itself is not difficult, it is just that when accidents happened, cars were often too fast or inattentive. This can be better controlled by bicycle. However, have someone more conservative leading your group, just in case. Since it is downhill all the time, the 60 km are possible in 3-5 hr, depending on the amount of stops and the weather. Front suspension is best, but full suspension is not needed—this is a gravel road used by cars before, it is not an off-road trail. Some tour companies offer their clients really bad and old bicycles, proofing the easiness of the road. Nevertheless, get a good bicycle—the most important thing are your breaks.
There is a check point along the highway, which is only open between 07:00—15:00. The first halt from La Cumbra is a sealed road. The North Yungas Road is gravel. Doing the trip on you won is more authentic, you do not have to start too early, it is cheaper, and you will have more time for yourself and pictures. In addition, it gives you the chance to visit a neglected but very versatile region.