Piñones Ecotours (Carr. 187 at Boca de Congrejas Bridge, 787/272-0005, fax 787/789-1730, ecotours [at] caribe [dot] net) offers biking, hiking, and kayak tours in Bosque Estatal de Piñones [1]. Gear rental is also available.
Links:
[1] http://www.moon.com/destinations/puerto-rico/east-coast/loiza-and-pinones/sights/bosque-estatal-de-pinones