Originally Posted by
pogonation
Personally I think 8 days is enough. Bangkok for 3 days, Chiang Mai for 4 days and Angkor Wat for 1 day. Personally I would want a few extra days in Chiang Mai and an extra day in Siem Reap but.
Bangkok Airways is the best airline for your routing. You could do airasia BKK-CNX but it's probably better to book through PK so you get connecting flights on the same ticket. PK is a really high quality airline and you even get a lounge when flying economy ^
Have you personally done Angkor Wat for 1 day? If so, my hat's off to you for your extraordinary stamina to cover such a big site in just a day - including the traveling time to Siem Reap...
Besides, the airfare to Siem Reap from BKK runs a few hundreds - would be a waste to fly such an expensive fare and visit a gigantic site for just a day but of course it is a highly YMMV.