Forming a cohesive unit with Palo Verde, the 26 sq km Reserva Biológica Lomas de Barbudal is a tropical dry forest reserve that’s famous for its huge diversity of resident bees. If that doesn’t make you want to come here, maybe the troops of white-faced capuchin monkeys will be more appealing.
In any case, Lomas de Barbudal is an accessible option for off-the-beaten-track independent hiking. A small visitors center has maps and other information. You can explore the reserve on four different hiking trails; Sendero La Catarata (waterfall trail) rewards with an amazing cascade that merits a dip.