Rodeo9112 Driving vs. Bus lines
Do you know the Caribe Tours station area well? How will you find the bus to follow? [There are lots of identical buses going in all directions].Is there a place that you can sit in a car, see the front of a Caribe bus, and then follow it? There isn't much space around to park or stand. I'm not suggesting that you can't do it, just that it's not real easy or obvious.
Do you drive a cab in Mahattan just to unwind on occasion?
Driving in Santo Domingo is pretty stressful/dangerous. If you can find the Caribe tours station and figure out how to follow the right bus, you can more easily just navigate to the north coast on your own without bothering. The chances of one of these buses breaking down is much less than your rental car breaking down, and if it did the bus line would handle it very professionally. On your own you'd get a bonus adventure.