Hi, as noted by Wreckdiversteve, the Hilton is about a 50 minute ride from PUJ along the highway (Dreams Onyx was about 40 minutes if memory serves me).
Bayahibe,as noted, is a fishing village with about 6000 people (local residents and those who chose to make it their home away from home). It is nowhere near as big or as touristy as PC and that’s one of the reasons I like it there and the other main reason, is the sea. I spent a little over a month there and had zero seaweed (other than on my visits to PC.). On all my visits to PC, seaweed was an issue but never had an issue in Bayahibe (nor family and friends who visited). By no means am I saying it doesn’t happen, but relatively speaking, it doesn’t come close to the seaweed in PC.
As for it being “rundown’, it’s like a lot of smaller places I’ve seen in the Caribbean. To me, it was a great experience in a place that is nothing like life in North America. I loved the happily coloured homes, music on the streets at all times of day and the generosity of the people who offered me lunch one Sunday on Bayahibe public beach. It’s not perfect but perfect for me.
I would never try to convince someone a place is safe. I spent a day in Madrid and had my wallet stolen in a coffee shop in broad daylight but spent several weeks in Bayahibe, used common sense and was fine. You do need to watch for cars/mopeds/bikes like anywhere. At the end of the day, if you are hesitating, it’s likely best not to leave the resort.