Travel Advice Please: Chiang Mai To Samui And Oethrs

[freesoul]

Hello, I wonder if any of you who are more experienced in these matters can offer some advice and answers to my questions:

Q1. The train trip from Bangkok to Chiang Mai. - Necessary to book before arriving in Thailand, or better when in Bangkok? I'll have 5 days there before actually leaving by train for Chiang Mai

Q2. I'd like to fly in the simplest and most economical way from Chiang Mai to Samui on the 7 July. I seem to find that the only flight is Bangkok Air at 5000+Bht. Any other suggestions. Many of the discount lines seem not to fly to Samui.

Q3. If arriving in early evening, how much time should one alllow from Samui airport to ferry by taxi?

Q4. Do ferry's operate in evening, or only during day. Any idea of latest time. I'm referring to ferry to Had Rin

Q5. And finally flying Samui to Phuket. Any suggestions of airline?

Thanks for taking the time read this and for your assistance

Kind regards

freesoul