Next month I'll have to drive from Bangkok to Ranong for a two days diving trip. By bus I understand it's a 9 hours ride, not exactly a short trip. How is the road ? Is it reasonable to make it in one go. Or better to stay overnight somewhere on the way ? Where ?

perfect road

head south to Chumpon than cross over to Ranong ( this part has some great scenery) Just drove it last week

MIn 9 hours and all depends on where u leave from in Bangkok

Why not fly if u can afford it