If you'd have 9 weeks total to plan Southeast Asia, how would you organize it? Starting from Bangkok. And do you think it's worth to visit all Thailand, Cambodia, Laos and Vietnam, or just staying longer in any of the countries and leaving others for some other occasion?
I guess in 9 weeks you can see a lot of those countries you mentioned, although better would be to skip Vietnam and focus on the other 3 so you have some more time to visit some more remote parts of Laos and Cambodia. The border between those countries is open for travelers since a couple of years, so you can make your way overland through Laos.
That's actually what I had in mind... skipping Vietnam because it should be easier... But I was wondering if I'm loosing too much or not. I guess It's impossible to do all and I have to accept to miss some very beautiful things.
I think 9 weeks is plenty of time for all four countries. Besides, since you are already in the region you may as well visit Vietnam. Each place is so different from the other, that you would have missed out on how Vietnam contrasts from the others. We did a long RTW trip - the SE Asia portion of the trip included Vietnam, Cambodia, Laos & Thailand, Mayasia & Singapore. Total time spent was about 11 weeks in SE Asia. We saw plenty of stuff and even relaxed for days at a time in Bangkok and Singapore - and did it all overland! I'd say that once you are there, you can see for yourself that it can be done in 9 weeks. In fact you can change your mind when you get there if you like one place quite a lot and want to explore more....When you make up your itinerary just give yourself options...