While staying at Natura Park (Punta Cana), I took the excursion to Boca Yuma. We stopped at Higuey, not just for the basilica, which I found very ordinary (in its kind, the new Guadalupe shrine near Mexico City is much more appealing), but also to see the local market. It was a unique experience, and a real opportunity to get in touch with the true DR. Do not expect an easy walk, especially after a shower. You won't be buying anything, but you will be able to say that you've seen something of the DR, things what most tourists do not get to (or do not want to) see...
One last tip: ask to do the tour with "Franklin". He is from Higuey and he has very interesting things to say... He speaks German, French - quite fluently - and enough English. Oh yes, people also speak Spanish there...
On the way from Punta Cana to Higuey, there is a place called La Otra Banda. A lot of money there (BUT there is an explanation. Ask for it), and pretty little houses. The street market is worth seeing.
The condition of the highways is atrocious. I would not rent a car.
Jean-Claude