It is apparently possible to get to Vientiane in Kayak from Vang Vieng; something that I really want to do. However I will have to sort out how it works with the bag, where we can leave it and if the company brings it to Ventiane.
Some travelers advise to use the company Wonderful Tours which are cheaper and very good according to the local guides.
As it won’t be the rainy season, I won’t get too much rapids a part from the ones on the following picture apparently: