Coach from SR to Bangkok is easy - two and three quarter hours to Poipet, fifteen minutes through Cambodian immigration but nearly two hours through Thai immigration. Then fairly quick to Bangkok (we went to Koh Chang).
#2 borisborough has been a member since 30/11/2009. Posts: 21
Yeah, it's a breeze from Siem Reap. The Thai immigration has always taken 5-15 minutes for me, but as boris says, sometimes, especially in the high season, it gets very crowded. Once on the Thai side, you can take a bus or train to Bangkok, around five hours. If you leave early, you can be in Bangkok in the afternoon.