Recommendation: Pack snacks.
Saying the journey from Laos to Vietnam via bus is long would be the understatement of the century. The bus ride from Luang Prabang, Laos to Diem Bien Vue, Vietnam (the first town you can cross into from Northern Vietnam) cost $28 and took 10 hours. The “Premium” bus I signed up for turned out to being local bus. If you've never traveled in Asia, I'd compare it to sitting in the back seat of the plane between two crying babies - crowded and overwhelming.
People are continually getting on and off the bus. At one point a man with a chicken in a backpack sat down next to me. When we finally arrived in Diem Bien Vue, I splurged for a hotel room so I could get a good night sleep before continuing to my final destination - Sapa, Vietnam. The next morning, I left at 6:30am for a 6-hour bus ride to Sapa. It was a rude awakening when I arrived in Sapa to freezing temperatures, rain, and lots of fog. I check into 'Capsule Hostel' which was an awesome place for only $7/night. To read more on recommendations for Sapa, click here!