Lunuganga is about a 1.5-hour drive from the airport or Colombo city. The Colombo-Bentota express train offers a scenic albeit longer coastal transfer or you can fly in via seaplane, landing on Bentota’s lagoon for a much shorter travel time.
Bentota has a good road connection with the rest of the island so getting to the hotel from other cities is fairly easy. From Galle: 1-hour drive, Kandy: 4.5-hour drive.