For the way from La Rasega over the Passo di Campo to the Lago di Malga Bissina at around 28 degrees, I needed about seven hours with the MTB including breaks. Driving is not possible on the ascent or the route is not worth mentioning. The bike has to be pushed and carried a lot. The descent from Passo di Campo is only possible in places for very experienced drivers. So also carry and push a lot.
Make sure you take enough water with you. There are springs with drinking water as far as Monte Zuccello. From Monte Zuccello to Passo di Campo, all springs run dry in summer. On the descent, it is worth jumping into the Lago di Campo; the route is very scenic.