Advice to all travellers in Thailand, only use authorised buses, the Thai buses are cheap and reliable , safe and comfortable,it may be advisable to wait an extra day until the authorised ticked dealer is open, if the authorised ticket dealer is closed if you are unsure, purchase 2 tickets, one for you and one for your baggage. Keep all cash , credit cards and passports, cameras etc on your person tucked in a belt under your shirt, never show large amounts of cash.never accept drinks or chocolates from a stranger even if they look wrapped and new. Hope this helps everyone.

I travelled from Bangkok to woah hin by train an experience in its self, but found Thai passengers so helpfull and friendly, the guy sat opposite me (hotel worker on his way home for day off) bought his lunch from a food seller at station stop and to my suprise handed one to me,would take no money and would not even let me buy him a coke because he had a bottle of water already. lunch was spicey as you can imagen but I suffered no after efects to speak of. yes be on gaurd but remember most Thai people are Budist and are brought up to be polite honest and helpfull, even though they may have verry little, they will not steal from you. I have seen more tourist behave badly than Thai. Enjoy your holiday to Thailand.

ALways use Chang Tour for Isaan ;) Theres no mafiosos, you get food and drink. They only stop at the bus stations. No roadside stops. Oh, and buy your tickets from Udon Thani. There is a shuttle bus that goes from the bus station to Udon.. It just takes 1 hour to get there. Beats waiting somewhere else for 1 hour, and you get to see another beautiful Isaan city while youre at it.
And yes, Trevor Matthews, I found the thai travellers very hulpful too. They helped me load my bags into the overhead compartment, and showed me how to tilt the chair back. Very, very kind. Never to be forgotten!