Full details coming soon. The following links should give you enough info to enjoy the trails though.
The Astroni Crater contains a WWF nature reserve of 250 sq km with lush vegetation, 3 lakes and several trails to explore. The public can only visit at weekends and by appointment – please use the following links to find out all the info.
WWF Astroni Crater (info re opening, booking a visit and 5 trails)
Napoli Unplugged Astroni Crater (more detailed info re opening and prices)