If you want to see more of Phang Nga's spectacular scenery and less of the crowds, take a speedboat.
Far more rewarding than the standard bus-boat tour, you can visit famous "James Bond Island," the interesting fishing village of Koh Pannyi, explore the mangroves around the edge of the bay, and the sea caves at Tham Lod.
After lunch, stop at Khai Nai for snorkelling and return to Phuket late afternoon.