We would be happy to book any shuttle you need right at the hostel. We are also happy to help you figure out how to get to anywhere you want to go. And you are in luck that El Zonte has one of the best tour guides in El Salvador, Rivas. We would be happy to introduce you to him and you can check out some photos from recent tours here. He is always on the move and going somewhere cool and his customers give him awesome reviews.
Shuttles are faster than local buses but sometimes not as fun! If you decide you want to go the slow way, check out this website to help you sort out buses and routes here in El Salvador.