Hi! I'm going to travel a couple of weeks (ish 14 days) next spring with som friends. Our starting point will be Singapore so the plan is to travel with plane to one of the major cities in those countries. And then travel around with bus and/or cheap flights.

So the only must thing we want to see is Angor Wat. Other then that we want to see some cool places in Laos and Vietnam with good nature and interesting buildings. Also thinking to spend some time, maybe 4-5 days on a place with a good beach. We also want to party some of the days we are there, but don't want a place like Phuket. So I was wondering if anybody had some tips about what we should see ? And a good way to get around between the different places (cheap flights or not too long bus rides).

So I think the best idea would be to fly from Singapore to some place close to a beach and be there 4-5 of days first. The problem is I haven't found any places that looks good close to one of the major hubs (Hanoi, Ho chi Minh City etc.) So any suggestions?

A example of what we could do would be something like this:
Fly Singapore - Ho chi Minh City, stay there a couple of days then travel by bus to a place with a nice beach. Be there for 4-5 days and then go back to Ho Chi Minh City and take a flight or bus to Siem Reap, check out Angor Wat and stay in the region for a couple of days. Then take a flight to north in Laos (Luang Prabang) and stay in that area for 4-5 days. Checking out the city and the area around it. Then take a flight to Bangkok/Kuala Lumpur where we will fly back home from.

The problems with this plan is that it is so long distances between for example Siem Reap and Luang Prabang and from what I've checked out these flights are quite expensive (300 US dollars). The Air Asia flight are cheap, but they only go to Kuala Lumpur etc. Not between the countries we are planning to visit. I think a bus trip might be very interesting if we go trough some areas with nice nature, but I think a 30 hour trip is a bit too long since we only have 2 weeks! So any tips on how to solve this in a cheap and cool way would be greatly appreciated!