San Fernando Island has a petroglyph just off the trail to the Mirador El Targon. Wildflowers to be seen along the way. The petroglyph is protected by a roof, as it is located atop a highpoint on the island. There's a good view to the west. On the way back, I watched a ball game.
The museum and gallery on San Fernando are very small but nice. We actually found the most outstanding collection of balsa wood carvings and oil paintings in the gallery here. While some of the artists do rather rushed work, there are several women who are quite dedicated to the genre of oil painting for which the islands are famous. These really are world-class paintings at a discount. The museum has a few archeological pieces and a variety of other exhibits about the islands. One feature of the islands are the solar panels and batteries used to produce electricity. While there are a couple of generators, there is an array of solar panels just up the hill from Jose Pineda's cabins. Although short of power and problematic, the solar system is quiet and renewable.
San Fernando has a narrow trail that circles the island, but there's also a footpath over the center of the island to Mirador El Targon, which has a view of a cove on the eastern side. I saw the bush bean agriculture and some birdlife.
Lonely Planet guide refers to this island as La Isla Elvis Chavarria, but Jose Pineda who lived there his whole life referred to it as San Fernando. Not, the largest but best located of the 36 Solentiname Islands, San Fernando is the island where we stayed. The small community is stretched along a concrete walk between Albergue Celentiname Hotel and the Museo. We stayed in Jose Pineda's cabins, which was next door to the museo. The walk has very pleasant views of uninhabited islands across the way.