What are the experiences and tips for crossing the border from Thailand to Laos via Udon Thani?

The user shared their experience of crossing the border from Thailand to Laos at the Vientiane border, highlighting the journey from Udon Thani, including bus travel and the process of re-entering Thailand with their O-A visa. They expressed that while it can be daunting for first-timers, it was a smooth process with no issues. They also noted their reason for choosing this border crossing was to enjoy a few nights in Nong Khai.