Hi, beginning from Bangkok what is the most efficient route to travel to Phuket, Koh Samui, Koh Phi Phi, and Krabi? We're planning on using train for the majority of (if not all) transportation and are fully prepared to spend many half days on trains. We need to end in Bangkok again as well.
Hope that made sense - all I'm asking for is something like "Bangkok -> Phuket -> Koh Samui -> Koh Phi Phi -> Krabi -> Bangkok" (I just made that up). Thanks in advance!

