bangkok to surat thani distance
Surat Thani literally means City of the Good People. It is the largest province of the South. There are an area of 12,891 square kilometres and bordered by the
Surat Thani is located 644 Km south of Bangkok, 84 km southwest of Koh Samui, and 290 km northeast of Phuket. It is divided into 18 districts and 1 sub-district

The topography includes a high plateau and forested mountains to the west, and low basins in the center and along the eastern coast. There are a tremendous number of island along the coast.
The islands of Surat Thani that you must go.
Koh Samui
The largest island in the region and a very popular tourist destination

Chaweng Beach koh Samui
Koh Phangan
The second largest island in the Suratthani province

Koh Tao
The diving and snorkeling “

Koh Nang Yuan
Three small islands connected with a beautiful double sided beach

Mu Koh Ang Thong
42 island with national park status, in the middle of Suratthani main land and the Samui island.

More infomation at Wikipedia