There is no Caribe tours bus from Santiago, you will have to take a gua gua. I know that there are about 5 of them that come to Samana each day. I have seen people get off the Samana gua gua and wait at the intersection after Sanchez to get the other gua gua to Las T. Its about a 45 min ride more from there. I think there might be a direct gua gua to Las T. as well but I am not sure as I have always used to the Samana gua gua which leaves from near the Street Las Carreras about 8 blocks down the hill from the monument. It is actually one block off to the right as you are going down the hill. It's on a one way street that goes the other direction of Las Carreras. Once again it is the gua gua to Samana. Maybe someone knows of the direct route to Las T.