When I Was Puerto Rican by Esmeralda Santiago (1993) is the best starting point for understanding the rural Puerto Rico that Gurabo represents. Santiago's memoir of growing up in Macun — a small interior settlement not unlike the communities around Gurabo — is vivid, specific, and unsentimental. It captures the texture of everyday life in the Puerto Rican countryside in a way that no travel guide can: the food, the family dynamics, the slow rhythms, and the complexity of an island caught between its own traditions and the pull of the mainland. Read it before you go.
The House on the Lagoon by Rosario Ferré (1995) is the major work of Puerto Rican literary fiction in English. It spans generations of a wealthy San Juan family and in doing so tells the story of Puerto Rico itself — its racial mixture, its colonial history, its class tensions, and its uncertain political identity. Ferré was one of the island's most important writers and this novel remains the best single work of Puerto Rican fiction available to English readers.
Moon Puerto Rico is the most practically useful travel guide for exploring the island's interior. It covers the mountain towns, the lechonera routes, the hiking trails, and the parts of Puerto Rico that the resort-focused guides ignore. Useful for planning a trip that goes beyond San Juan and the beaches.
Puerto Rican Music and its Performers — the pasillo that gives Gurabo its nickname is one thread in a rich musical tradition. For background on Puerto Rican folk and popular music — the décima, the bomba, the plena, the danza — any of several academic works on Puerto Rican musical culture will provide context. Ask at a university bookshop or library for current recommendations.