OK...I made that trip in July last year. What we did was drive from Sto. Dgo to Barahona (about 3 hours) and stay there as there's not much in terms of accomodations anywhere else in that area of the country. We stayed at the Hotel Larimar which is next to the sea, byt the Malecon. I didn't look for hotels ahead of time and this one looked the nicest one around. It was not very good and very expensive for what they have to offer. I guess there is a nicer one in the area "Barcelo Bahoruco Beach Resort". Hotels in the area are not nearly as nice as other more touristy places such as Puerto Plata, Punta Cana, etc...
There's a restaurant a few blocks from the Hotel Larimar, which was actually pretty good. It's called Los Robles.
Next day we drove to Pedernales. Our destination was Bahia de Las Aguilas. The views on the way there are just amazing. The drive is pretty long though, but the roads are pretty good except for a couple of places where it got washed out at one time and it had not been repaired yet. There are quite a few beaches on the way there (Lost Patos, San Rafael, etc), but we didn't stop at any of them as we wanted to make it early enough to Las Aguilas. If you go to Las Aguilas make sure you drive a 4x4 AWD SUV, otherwise you won't be able to make it to the beach as there's a pretty steep hill you have to drive over. You can take a boat (about 10 minute ride), but you have to leave your car in the little village and they charge 1200 pesos for the ride. There's really not much in Pedernales itself.
Also take any food, drinks, etc or at least make sure you have a good breakfast before you head out that way, as there's nothing between Barahona and Pedernales once you go past the little towns close to Barahona.
The beach at Bahia de Las Aguilas is amazing, but there's nothing there. Not much shade either. The day we were there we probably only saw about 10 other people the whole time we were there. Obviously make sure to use lots of sunscreen. I got sunburned really bad...which was no fun a day or two later.
Next day we went to several places (Jimani - crossed into Haiti for a bit, which wasn't really worth it, The Magnetic Pole and Enriquillo Lake). By the time we made it to the lake it was almost 4:00 PM and they weren't taking people to where the crocs and flamingos are. By then we were kind of tired anyway and just headed back to Sto. Dgo. If you go to the lake try to make it early enough so you can tak the trip to see the crocs, flamingos, etc.
One thing you should know is that there are many army checkpoints around the area. On you way there (towards Haiti) they won't stop you, but on the way back they will stop you at each one and they will ask for ID. I didn't know about this and had my wife and kids with me. They didn't have ID with them, so I ended up having to pay a bribe a several of these checkpoints for them to let me go and not give me any grief. If they see you're not Dominican they will try to take advantage of this, so make sure to have ID (passport or license).
Hope this helps.
