Stay: Mandarin Oriental Bangkok - I stayed here over Christmas in 2015. This is a beautiful hotel that evokes a bygone era of Thailand, called Siam when it was built as The Oriental in 1876. You could only arrive by boat on the Chao Praya, or River of Kings. Today, the property is divided by this mighty river, with the spa and a couple of restaurants on the other side (shuttle boats are constantly running). They've just reopened the Author's Lounge, and it feels like Somerset Maugham should be there. The breakfast buffet is expensive but one of the best I've experienced around the world. Just don't put your feet in the pool after official closing time - we not only got reprimanded, but also "reported!"
Grand Hyatt Erawan Bangkok - I immediately felt relaxed in this beautiful city hotel. The lobby is enormous and welcoming; the rooms are intuitive and sophisticated. It is surrounded by the futurama chaos of Bangkok's biggest malls, like Siam Paragon, and is an ideal location for exploring this part of the city. I loved the pool and club level lounge. I would definitely stay here again if I return to Bangkok.
Stay: Dhara Dhevi Chiang Mai
Shangri-La Chiang Mai
MUST-DO: Elephant Nature Park