Approx as I remember about 3 1/2 hours to Santo Domingo and 7 hours to Puerto Plata from Barahona. Maybe the highway has improved the last 2 years and road signs near Santo Domingo as well.
You're correct about travel time west from Santo Domingo to Barahona. Highway is good...getting from Las Americas through Santo Domingo and to the highway is H E doublehockeysticks.
