After I get through Customs/Immigration, I know that there are little minibuses frequently leaving for David. Is my best bet to catch one of these as far as La Concepción, and then catch another minibus towards Volcan? Or is there a better way to do it? And how frequent are the buses between La Concepción and Volcan? How long would you estimate it takes from the Panama side of Paso Canoas to Volcan - about 3 hours?