I had the best time of my life in Chiang Khong! Don't miss it! Go to the Bamboo Riverside Guesthouse for AMAZING quesaldillas and then on to the Tee Pee Bar ("like a rat hole - you can't miss it.") For music and entertainment all night on guitar. Sing along and bring a guitar if you have one! Just watch out for the dogs on your way back to your hostel!
On the way from Chiang Khong to Chiang Saen, it's great to rent a motorbike for visiting the old city.
Chiang Khong city is a small and quiet place with a great view. People are very friendly. There's no nightlife. It's cheaper to stay here before crossing Mekong River to Laos.
Now Tee Pee Bar is closed for a long time. New Bar is next to Madam pub (only one in Chiang Khong).
Chiang Khong I was here for a few days. I visited Hmong Hilltribe Village here. It's ten kilometers from city by bike -- nice people and simple life.