It's already long time I had a bus journey from Khon Kaen to Chiang Mai so I forgot how horrible experience it was.

 

Now planning to visit Pattaya and travel by bus. What is the best option - Nakhonchai Air has buses on this route, 1st class perhaps?

I'd take the sleeper train down to Bangkok and then continue on either train or Bus from there.

 

Thats a hell of a trek on a Bus probably 12+ hrs

Nakhonchai Air always receives favorable reports, when we pass their buses on the road the drivers are usually well behaved. Another option of course is train to Bangkok and then a bus, but I imagine you've already considered that.

18 minutes ago, LingonBerry said:

What is the best option - Nakhonchai Air has buses on this route, 1st class perhaps?

Seems like Lion Air would be the best option from cnx-upt. 

Nakarn chai air  VIP  coach from Arcade bus station to sukivit road Pattaya. First class service. 

For me: Nakhonchaiair no more.

 

Arctic cold in the bus for many hours, more than 13 hours from Chiang Mai to Pattaya,

and the design of their seats makes it unable to stretch the legs.

 

I better go through Mochit, changing the bus to Pattaya.

Why not fly?

What's the best way to get to Pattaya from Don Mueang?