Hi Simon,
you and I met many years back when I was riding the motorcycle around the island selling wine. Agreed, Phuket is definitely "not what it used to be", that being said, no where is.
What you said about Khao Lak, perfect, I like quiet beaches. When I need to see friends in Phuket or get in the party mode, will jump the bus, get a hotel room.
Good call on Kanchanaburi. I spent some time there, loved it. Can imagine a little place near the river, fishing kit, cooler of drinks. Fish on the grill. Enjoy brother, cheers, GOM