what is the best way to get 6 people from the port in Nawiliwili to Hanalei Bay
The Guru Take
Taxi or Rent a Car!
At this point in time it looks like a taxi or black car service would be your only private for hire option. See below.
However, you most likely can rent a car for a day or look into the areas public transportation system if one is available. Both of these options may be more economical!