I would rent a Car ,and enjoy the drive... Once you get past the crazyness of Samana City it is like you stepped BACK IN TIME, and you dont want to miss a thing .. its that nice .. You could also stop in Samana City to look around briefly and maybe check out where to catch the Boats to Cayo Levantado ( a MUST see at least once) so you familiar with it,, but with luggage probably a good idea to leave someone in the Rental car..but its a nice little stop along the water front.
Then along the rest of the ride, enjoy the sights of coconut trees , but make sure you arrive in Las Galeras before dark, as you need to know where to go once you hit town which is very small but you can still make a wrong turn.
But be sure to Stop along the way ( there is really only ONE road , after Samana City, you literally cant get lost ) to buy some Bread or Bananas , or drink coconut water, enjoy a cold Presidente with the windows wide OPEN . You wont regret it ..
I'm getting all verklemt just thinking about it .