You can take any of the big buses heading for Takuapa, Ranong or Chumphon from the main road.
I rode a bicycle from Phuket to Takuapa and saw many aforementioned buses passing me on the way to Khao Lak.
As I recall, Khao Lak had a visible Scandinavian presence when I was there in early February.
The main road runs north-south for several kms in the Khao Lak area. Khao Lak National Park is perched on a mountain just before the town, and several breath-taking viewpoints are located next to the main road. At least three wats can be found in Khao Lak, and at least one will leave you bewildered (search on Google Map). A navy ship that was swept away by the tsunami has become the focal point of a museum there.
Overall, Khao Lak has more of an Ao Nang (Krabi) feel than bling-bling, Las Vegas-like Patong.
Many parts of Phuket have sacrificed their natural innocence for commercial redundancy. For this reason alone, Changwat Phang-nga should be forever grateful to Phuket for taking the low road.
I am tempted to say that educated foreign tourists fly into HKT and then leave immediately for neighboring Phang-nga. Meuang Phang-nga will be a pleasant surprise.
Changwat Phang-nga is where one will find authentic Thai culture with countless beauties to be discovered.