Maybe my timings are off. When I was there I had driven from BKK to Khao Lak, then my partner had to fly from HKT back to BKK for the weekend. During that time I stayed at the Westin.
I came north from Khao Lak and after the airport it was further down south and on the eastern side but I didn't perceive the drive from the airport to the Westin after dropping her off as a 45 minute trip.
Anyway I just realized you were quoted 3500 *return* so that's a bit more realistic. I initially mis-read it as 3500 one-way so I freaked out.