Thailand has so many attractive places where you can spend your holiday, it depends on what kind of scenery that you like. Some people love beach, so they will pick Phuket Samui, Krabi etc. As for the ones who love nature, country side peaceful and isolation I would love to recommend The Floating Raft House at Vachiraprapa Dam in Surat Thani province.
If you need further information about this trip, please let me help you.
Best regards,
Supparin