Drive from Bangkok to Ko Lanta

I’ve previously driven this a couple of times and know the route (4/41/44),lastly 2 years ago. I recall lots of roadworks and wondered if they’re largely complete now and any other tips (speed cameras etc) that now apply? We’re spending first night in Cha am for separate reasons and want to stop one more night somewhere between there and Lanta before completing the  journey taking in some sights en route. Stayed in Chumpon previously which ,apart from the great viewpoint, I found rather uninspiring as a town but it may do again simply as a convenient geographical location. Unless there are any other suggestions? Also any other suggestions for points of interest en route that I may previously have overlooked. I did the emerald pool and stayed in Bankrut too so wondered if I was missing anything obvious? Not so interested  in temples unless they incorporate a great view / interesting drive.