The journey into town takes about 20 -30 minutes depending on traffic etc. If you want to see your journey Hobomaps have good maps of Vientiane. http://hobomaps.com/VientianeRegionMap.html This worth checking out.
Starting from the bottom left map (ref LT309 ) is the train station in Nong Khai from where you need to tuk-tuk to the border. Tuktuk for two from Nong Khai rail way station to border should be 40 baht or less. They will try and take you to get a visa along the way. DO NOT STOP you can get a visa on arrival at the border a couple of minutes away – without needing to pay a fee.
Once through the immigration/visa formalities you will be bombarded with taxi offers (if you haven’t already been approached in the immigration area) Prices are about 300 baht, $10.
A shared minivan or truck should be about 100 baht per person. A number of minitrucks park over at the bus stand and you can get a ride on these for similar price as the bus – now 6,000 kip – many locals use this service. You just need to check where they are going.
Bus 14 goes all the way to Talat Sao, the morning market in the city. From here you can pick up a tuk tuk or walk to your accommodation. Pile on and pay your fare when you get off the bus. These can get crowded but do travel regularly. The bus is best if you do not have much luggage to manoeuvre.
On your journey into Vientiane you will see the Beer Lao factory on your Left and the Pepsi factory on your right…and then lots of local Lao city fringe life