Very nice route, the first 10-15min you ride along the sea coast. There are many roots but not a problem. I would recommend it to anyone with little experience. Still, its not a track for first timers.
If you are on the paseo littoral on Mayaguez you head towards Joyuda. When you climb the mountain of Joyuda after you go down turn right(U-turn) and keep going until you see the Recursos Naturales Lab. Here you will see the track entrance.