I hiked the Cabo Cabron yesterday. And I survived. What you must know before you go is that this is a national park, and their are a few trails and trailhead crossings, and that it is a very large park with few other people hiking and no maps. But there are wonderful views which make it a worthwhile excursion for an experienced and prepared hiker.
Our group had a guide who told us that it would be 1.5 hours in and 1.5 hours back after reaching the beach for a wonderful swim. The group of 14 ranging in ages from 5 to 73 plus two large dogs, took back packs of water, lunch, snack, towels and cameras. Our group have various levels of experience as did the 2 guides who took us in. It was a 3 hour hike in and 4 hour hike out (only because we kept the group together and made many rest stops on the way back because we had all run out of water). Had we been prepared, we would have had sufficient water, food, extra snacks, etc.
The trails are difficult because there are many rocks that are dislodged on steep inclines, and fern gardens that cover paths so that you cannot see where your foot is placed. But if you are an experienced hiker, you will see many beautiful vistas, the beach of Rincon, the serveral layers of forest, some iguana (which are being reintroduced into this area in order to save the endangered species) and the flora is wonderful.
Let me warn you that there is no beach at the end of the road but there is a volanic area in front of the water where you will want to jump in and cool off. Its a treat and you can snorkel there, but would be better advertised as an inlet surrounded by volcanic rock.
Also be aware that you will not be able to get to a trail head to get into the park without a 4-wheel drive and some very serious suspension.
I would do the hike again with more water and better preparations. I would also veer towards the Playa Rincon for more spectacular beach front.