Our family of four (two 9 year olds)will be taking the overnight train from Bangkok to Chiang Mai. We want to take the 19:35 train that arrives at CM at 9:45. Can someone explain the main differences between 1st and 2nd class on this train. Both are air con so I think we would be comfortable either way but I want to know what I'm getting into. Also, has anyone tried to book this in advance through the Thai Railway? It appears that you can book this via email 30 days prior to departure with only a small surchurge. The other services seem much more expensive (thaifocus, traveller 2000, etc). We will be arriving during high season (Nov) and will need to book prior to arriving in Bangkok. Thanks in advance for the help.