Sorry, I've been away from this forum for a couple years. My niece, who lives in the country just told me the Carnival port is open. We are long-time visitors to the DR (coming again in Nov) but also have cruised a lot on big lines in the Caribbean.
I just went over to check on the Cruise Critic site. Huge site, consulted by many cruisers about different ports, tour providers, towns near the port, and so on. It's free to become a member, so it is a good site for monitoring how Carnival cruisers are feeling about their experiences in the new port near Puerto Plata.
So far I can say many people are already booked on future cruises that will dock there, and they are searching for excursion opportunities and information about local sights and activities. They seem to be having trouble finding many options. The tour companies who already have web sites and who give an easy way for tourists to email them (and then get back to them promptly) are going to do very well. Those who think they can hang around the port hoping somebody will take their tour will be getting the leftovers.
Some cruisers will always book the cruise ship's own excursions, even though they are more expensive and not as good. It makes them feel safe. But many don't want to be stuck on a bus with 50 people, some with walkers and canes, that moves as slowly as the slowest person. These people are looking at the web to find small van tours of 8 or 10 people, with a planned day of about 6 hours. Maybe three interesting stops and a beach for a swim. They want to book online and get an answer within a day or two to their emails. They expect a cooler with drinks - cold beer and pop is usually what they get. They want a reliable vehicle, a driver who speaks English and who will tell them what they are seeing, and above all, they want to be assured they will get back to the port before the ship sails.
I am getting the feeling from Cruise Critic site they can't find much on the web for this new port. It costs almost nothing to get a basic web page up, with email capability. However, you must answer the emails promptly, or they begin to doubt you. Even taxi drivers with a decent car can offer this service via the web - I know this because I booked a taxi in Turkey online. The guy answered my email, he showed up, and we were happy to pay him $250 for five hours to take us around.
That's how people are going to make money from this new port. Pass the word.