Is there a bus route going from Chiang Mai to Surin? I know there is one going the other way, Surin to Chiang Mai but I can not find what bus company has a route from Chiang Mai to Surin..... can anyone advise?

You might ask at the bus station at the NCA bus line office. The web site is www.ncatour.com and the phone number listed is 02-936-3000 The web site is only in Thai. I can say that the booking process over the phone was very good for a bus ticket on an excellent bus from Buriram to Chiang Mai. This bus company has several classes of bus, with only a small price difference to be booked on the best bus model in their fleet. NOT brightly painted double decker buses that you see roll back and forth, but newer White buses. There are some food stops included in the ticket price.