Go try and stay somewhere rural for a little bit in the Valle Central - East of San José - because it's absolutely beautiful there. Make sure to cycle down the coast from Puerto Viejo de Talamanca in the south west if you can, bike hire is dirt cheap. To find actual tourists and most of the beaches you need to head to the west coast though. Nicoya Peninsula is nice enough but a bit of a pain to get to coming from somewhere like Puerto Viejo