Siem Reap to Bangkok

Here is a quote taken from seat 61

• Option 1:  The fastest journey from Saigon to Bangkok takes 2 days, 1 night.  Day 1, travel from Saigon to Siem Reap on a direct morning bus, see here for details.  Stay the night in Siem Reap.  Day 2, take road transport to the border at Poipet and the afternoon train from Aranyaprathet to Bangkok, details here.  This won’t give you any time to see the Angkor temples, so I’d suggest extending the journey to 3 days to give 2 nights and one full day in Siem Reap to visit Angkor.
• Option 2:  Here is a less hectic option, taking 3 days, 2 nights and avoiding the long 12 hour bus ride from Saigon to Siem Reap required in option 1.  I also highly recommend the speedboat ride along the river from Phnom Penh to Siem Reap.  Day  1, travel from Saigon to Phnom Penh on a direct morning bus (6.5 hours), see here for details.  Afternoon and over night stop in Phnom Penh.  Day 2, take a bus (5 hours, details here) or better, the river speedboat (6.5 hours, details here) from Phnom Penh to Siem Reap.  Afternoon in Siem Reap.  Day 3, in the morning take road transport to the border at Poipet and then take the afternoon train from Aranyaprathet to Bangkok, details here.  Doing this route in 3 days will only give you a few hours to snatch a quick glimpse at Angkor Wat, so I’d recommend stretching it to 4 days to give 2 nights and one full day in Siem Reap to visit the Angkor temples.