Muy chevere la bici. I was going to recommend more of a road style entirely, but then I wondered what kind of terrain you're dealing with there and then you answered the question before I could ask. I lived in south america for a while and many of the roads were dirt and perpetually muddy during certain times of the year, but I've never been to Costa Rica (though I would like to.) So the setup you have is probably ideal unless you want to buy a cyclocross bike which is always my first option as a commuter. So yeah, fenders would go a long ways in keeping you and your bike clean.