The village of Dois Rios is a tough 8 km hike across Ilha Grande. Near the halfway point summit on the road there is a trail (Trilha 14) that leads sharply downhill through bamboo groves and steep jungle forest. This trail reemerges on the road and cuts off the two long switchbacks. In Dois Rios the beach is a long curve of pure sand, clear calm ocean, and very few people. You may be able to buy mineral water, beer and a sandwich to enjoy your beach day. After lunch you should explore the small museum facing the dynamited ruins of the presidio, where political and criminal prisoners were incarcerated at various times between 1930 and 1994. After the last prisoners were transferred to Rio, the place was blown up and left as rubble. The townsite has that eerie quality in concert with abandonment despite the recent addition of a university research facility. There is a restaurant there serving comida caseiro. And you should sign in and out with the guard at the gate who will tell you with a knowing grin that there is no bus or taxi service here, so hit the road with enough water for the long hike back to Abraão. Watch for monkeys. There was a troop of browsing primates - black Howlers that are much bigger than capuchins - near the lower intersection of Trilha14 and the road. Get back to Abraão before sunset.