We spent the night in Chiang Khong, on the Thai side of the river, and early the next morning, took a little motorized wooden ferry over the river and crossed into Laos.  From there, we took a river boat down the Mekong River for two days to reach Luang Prabang.  The ride down the river was enjoyable; we saw fishermen with their nets, hill tribe villages, lots  of green hills and the occasional speedboat noisily zipping past us, its occupants sporting crash helmets.