“La Elvis” owes its name to a young martyr who participated in the 1977 raid on San Carlos [1] and was subsequently captured and killed by the National Guard. The island has a health center, a school (Escuela Mateo Wooten, named after the Peace Corps volunteer who led its construction in the mid-1990s), a museum, and a hiking trail.
El Museo Archipiélago de Solentiname (MUSAS) (at the top of the steep path out of town, open 7 a.m.–noon and 2–5 p.m. Mon.–Sat., $2) was built in September 2000 to preserve and display the natural and cultural heritage of the Solentiname Islands [2] and its people. The flowers along the path on your way up were planted to attract butterflies and hummingbirds.
Inside, local artists have painted scenes of the islands’ early history. Also find interesting maps of the area, archaeological information, and a display of traditional fishing techniques and the balsa-wood carving process.
Behind the museum are a natural medicine garden, arboretum of 42 tree species, a model organic avocado and balsa-wood plantation, and a weather station.
The Fundación MUSAS (made up of six community leaders, the Italian NGO ACRA, and several other organizations) also organizes environmental education workshops in the island’s school and supports a number of research projects in the area. The museum is open daily, but if you find it closed, ask around for Socorro, the local curator, caretaker, and key master. For more information, contact ACRA in the Managua [3] office (tel. 505/249-6176, musasni [at] yahoo [dot] com).
At the peak of the dry season (March-April), La Cueva del Duende becomes accessible. It is usually underwater and is an important archaeological site that the islands’ past inhabitants believed to be the entrance to the underworld. They painted faces to represent their ancestors, believed to reside there, and left other markings, including a female fertility figure. The cave is located on the nearby Isla Donald Guevara [4], but you can arrange the tour with CANTUR here.
Doña María Guevara has been running the 
Albergue Celentiname (tel. 505/8893-1977, celentiname7 [at] yahoo [dot] es, $50 for a double room, rate includes breakfast, lunch, and dinner) since 1984 on a beautiful point at the western edge of the island. She and many of her family members are painters, participating in Cardenal’s project since its earliest days. All of the electricity in the hotel is solar generated.
The eight cabanas have capacity for up to 25 people, all with private bath. There is a picturesque porch, a bar, and a comedor. The flower-framed views are priceless. Kayaks and fishing gear are available for rent. Try to make reservations in advance if possible. They can help arrange for transportation when it’s available, but expect round-trip transportation from the island to run upwards of $120.
Several hundred meters east, with his own dock on the southern shore of the island, Don Julio rents three rooms in his rustic and comfortable, lakefront homestead for $6 per person. Don Julio’s brother, Chepe, runs transport to and from San Carlos [1] and can arrange custom trips.
Their sister Doña Maria Magdalena Pineda has her own hotel another couple of minutes east along the shore: Cabañas Paraíso (tel. 505/2278-3992, gsolentiname [at] amnet [dot] com [dot] ni, $35 d with three meals and private bath) also has a comedor, rents kayaks, and offers tours around the island and beyond. They also have an office in San Carlos and a gallery in Managua, plus excellent local guides.
Links:
[1] http://www.moon.com/destinations/nicaragua/rio-san-juan/san-carlos
[2] http://www.moon.com/destinations/nicaragua/rio-san-juan/the-solentiname-islands
[3] http://www.moon.com/destinations/nicaragua/managua
[4] http://www.moon.com/destinations/nicaragua/rio-san-juan/the-solentiname-islands/other-islands