When you have finaly crossed the border you will be accousted by all manner of taxi drivers. Best thing to do is just get into town and ditch them. They will want to take you to a hotel of their choice, saying that the one you want is clossed or full and they will want to sell you a bus or boat ticket telling you whatever they need to do this. Get across the bridge. If you can get them to take you to your hotel then do so. Ko Khong guest house is O.K. Otherwise just get them to drop you at the river near the bridge and walk there. You can stop for a beer at Cat bar and ask John about rooms too. Ko Khong guest house is next door.
Don't belive all the moto taxi stories about robberies and murders. They are just trying to scare you. Ko Khong is a fantastic province to explore, but the taxi drivers scare off a lot of People.