For any ones who would love going to mountain more than sea, I would recommend Nam Nao which is well-known as one of the most beautiful National Parks of Thailand. (It covers an area within Phetchabun and Chaiyaphum province, in the northeast of Thailand) You will be impressed by the beautiful and fascinating landscape and the air is really fresh. The weather is very pleasant; i.e. the temperature's average is 25C in the day time throughout the year. It is rather cool during the night time and early morning. And it will be really cold at night in winter season. (during December - January) Besides, you will enjoy the feeling of the tranquility Day and Night as well.
I do believe that by travelling to this beautiful national park, your dream is closer than you think. Stop the time and spend your vacation at Nam Nao, one of the most beautiful national parks of Thailand. Have a wonderful trip!