In short
Vang Vieng is ringed by limestone karsts riddled with caves, on the banks of the Nam Song. The landscape recalls Guilin or Ninh Bình, smaller and more accessible.
The town long had a river-party reputation that caused deaths and led the authorities to close the bars in 2012. It has since turned towards ballooning, climbing and kayaking.
What it really costs
Housing and food cost little. The budget turns on activities: a balloon at sunrise, tubing, kayaking, caves.
The high-speed railway now links Vientiane and Luang Prabang with a stop at Vang Vieng, replacing four hours of mountain road with one.
What nobody tells you
Serious methanol poisonings have been reported in Vang Vieng, linked to home-made spirits served in some bars. Sealed bottles of a known brand, or local beer, remove the risk.
Unexploded ordnance remains a reality in Laos. You do not leave the marked paths around the caves and the rice fields.
The rainy season swells the river and makes tubing dangerous. Some activities are suspended, and that is not negotiable.