This is one of the new Hiking/Biking routes laid out in Murcia. This section is the link El Paretón – Gañuelas – La Majada.
It is part of the extensive Campoder GR 257 Trail. They are mainly off-road routes and can be very technical in places for bikers. (Where you see the sharp u-turn on the route, there is a very steep rough & rutted ascent/descent.)
The route is extremely well signposted, navigation on the route is not really necessary.
The route is a wide, standard Spainish track with numerous steep ramps along the whole route. It made be too tough for many casual bikers, but is a real MTB'ers dream. The photos of the track do not do the steepness and difficulty justice. Parts of the route may also get washed out after heavy rain leading to very deep ruts.
However, the route goes through very wild & scenic country so give it a go, but be ready to walk in places!