We went to Thailand for 2 weeks, in December as we were trying to get away from Europe's cold weather. We stayed in Phuket & Koh Yao Yai and used Phuket as a center point to visit the Phang Nga bay islands & nearby beaches.
Patong is probably not the best choice to see Thailand, but we found it useful to use it as a base for traveling around. It's also a good place to grab a good coffee or delicious meals. We spent most of the time on Karon beach, which is really nice and not that crowded, and it's not that far to get too (we used Grab to travel around).
We took a boat tour to the Phang Nga Bay, with Mr. Not's tour, to visit the James Bond island, kayak around the Hong islands and Koh Panyee - an amazing Muslim-only village in the middle of the bay.
The muslim village, Koh Panyee, is something you can find pretty hard to imagine. All the houses are floating, lack windows and in general they are very basically equipped. The typical interior deco consists in a bed or a couch, a table and sometimes a TV. Everything they have is to sustain a very simple life.
They have a school and, of course, a football team. Their energy supply relies on a generator and their meals are usually consistent from what they fish and rice.
Koh Yao Yai
We went for 2 days in Koh Yao Yai (and that was way too less), and stayed at the Santhiya resort - by far the best place I ever stayed in.
We spent the time there either doing stand-up paddling & enjoying the private beach or getting stuffed with all the amazing food there. And fall in love with this amazing sunsets.