The point of going to Phuket, Krabi or Hua Hin is to relax. There is no need for a serious itinerary. These locations offer all kinds of accommodations from five stars to mom and pop guest houses. Great seafood and southern Thailand cuisine is abundant. And of course, if you are staying at a luxury resort, western types of food are abundant. High end spas and less expensive Thai massage joints are available to relieve stress and soothe your muscles and minds. If sitting by a pool all day or laying on the beach is just a little too inactive for you, there are numerous golf courses where you can rent some clubs and chase that little white ball all day long, caddy included. Day-long snorkeling trips, such as to Phi Phi Island, can give you even a closer up view of the paradise found in southern Thailand.
Sources:
www.thailandtourism.org
The Lonely Planet Travel Guide: Thailand; Seventh Edition
www.bangkoktourist.com