Thanks for your help guys. Yep, he had heard that we had to go to Higuey to get to Boca de Y - it just seems so mad to have to go there on a 45 min journey and then take a more local one to go the smaller distance but takes the same time. We had hoped that we could catch a bus to take us to the fork of the road and then catch the Higuey one going down the secondary road.
Yep, getting a car is also an option - but that is quite expensive and hiring a taxi... hmm, yep could do that too bt that will also be expensive.
i don't know "what you heard from somewhere", but from Bavaro/Punta Cana to Boca de Yuma Higuey is located exactly on the ONLY road to go there, no main roads or sidetracks, there's only one road. Higuey is located more or less on half distance on that journey, so the travel times provided by LauraJane are accurate.
coming from bavaro you have to switch the bus anyways, Higuey is the plattform from where the busses for all the different destins depart, to miches, el seibo/hato mayor, boca de yuma, la romana, san pedro and to santo domingo.
if a rental car for one day is too expensive then forget about the above mentioned option to "hire a driver" or take a cabby, that would cost much more.
in an area with just one road there's not much chance to hit the wrong way, lol.
good luck
Mike