From Laos to Cambodia through Thailand

My girlfriend and I are traveling through Thailand, Laos and Cambodia in feb, and are stuck on one leg of our trip. We are trying to get from Vientiane to Siem Reap but we don't have the luxury of time or money. So we are wondering what is the quickest way that isn't too expensive. Bus? Or fly from one border to the other inside Thailand?

From Vientiane to Siem Reap it's only about 6 hours by bus. It is much advised however, to break the journey at the lovely town of Vang Viang about halfway between.

Think you may be a little lost of you are passing Vang Vieng on the way to Siem Reap! From Vientiane you can take an overnight bus down to Pakse in the South then continue through the Four Thousand Islands and cross the border here before making your way to Siem Reap. While this would make a great trip, its going to take a few days.

You could fly from Pakse to Siem Reap which will cut your flight costs down. The quickest way without flying would be to go into Thailand and cross into Cambodia from there.