This article will be very very short and you know why? Because I have spent 5 days, 5 little days in this country. Let me present yourself Laos.
Luang Prabang the place to chill
I have seen lot of big city but never like that. In Luang Prabang you can walk easily and safely in the street. There are just few cars and motorbikes. You can also find a temple each 100 meters and cross lot of Buddhists in the city. The atmosphere is really peaceful and perfect for a chill break in your trip.
Close to Luang Prabang (around 1 hour) you can see a beautiful national park with a lot of awesome waterfalls and some bears. I think is the best activity around Luang Prabang.
2 days on the Mekong
If you plan to cross the country from east (Vietnam borders) to west (Thailand borders) you can take a slow boat on the Mekong. The most famous Asian river is another kind of transport, better, I think, than a bus or a train (too classic).
Anyway, with a boat you can enjoy a quiet time without tourists, see beautiful landscape and, between the 2 days, stay 1 night in a small village with local people.
Was a short time in Laos but, as you can see on the pictures, was a really good time.