Driving from north to south, take Highway 52 across Puerto Rico and exit at Guavate to follow the Ruta Panorámica through the interior towards the west.
If you like, make a short stop in Aibonito, the highest-elevation town on Puerto Rico.
The Ruta Panorámica continues over the mountains to the Cañón San Cristóbal, a canyon 1,210 m deep. As the canyon paths are extremely steep, only experienced hikers should attempt the descent.

The road through the Toro Negro Forest is practically enveloped by bamboo on both sides.
If time allows, definitely drive this gorgeous longer panoramic route.

Alternatively, you can take the express roads – Route 52 heading west, then Route 2 from Ponce onward.