I traveled from Ayutthaya to Surim by train. People coming from Bangkok (480 km away) can either take the train, which takes slightly longer (8h) or the bus (around 7h) There is an overnight bus, arriving near 4 a.m, but I know nothing about its safety and comfort. From Ayutthaya, the trip takes around 5 hours, which isn’t much. However, the first one departs around seven, arriving past 12.