Can you suggest a preferred taxi for transfer from airport to heldrich hotel and conference center?

Uber and Lyft

Train station is walking distance. Uber is available.

The heldrich is an easy walk from the New Brunswick train station or you can take a taxi or Uber

I used the Airport Taxi and Uber to get from and to the Newark Airport (45 mins). Both seemed OK.

I'm sorry I don't know any local taxi companies. Uber is available in the area I assume you need the transfer from Newark airport. It is at least 40 minutes drive. The Hotel can arrange a taxi for the return journey. So it might be worth calling them to see who they use